Growers Network Glossary


The “Growers Glossary” is intended to be a living, breathing reference and index of terms we use in our ongoing Growers Spotlight series.


Index

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Glossary


A


Abamectin

Abamectin is a commonly used pesticide and miticide. Abamectin is frequently used in fruit, vegetable, and ornamental plant production. While widely considered safe in small amounts to most mammals, heating of abamectin can result in rapid (and sometimes explosive) combustion and a mixture of toxic compounds, making it unsuitable for use with cannabis.

Articles referring to Abamectin:

  1. The Wrong Way to Use Chemicals and Pesticides

Acequinocyl

Acequinocyl is a miticide frequently used in fruit production and has a half life of approximately 16 to 39 days depending on environmental conditions. It is not considered to be of high toxicity to humans. No tolerance has been yet established for cannabis, so use is not recommended if a grower wishes to remain compliant.

Articles referring to Acequinocyl:

  1. N/A

Adenosine Triphosphate (ATP)

Adenosine triphosphate (ATP) is a nucleotide that acts as the basic unit of cellular energy. It can be produced via glycolysis, the citric acid cycle, or electron transport chain in eukaryotes. Most cellular functions need energy in the form of ATP.

Articles referring to Adenosine Triphosphate:

  1. N/A

Aeration

Aeration involves supplying soil and roots with air or oxygen. Geolite is an example of a medium with excellent aeration. In some hydroponic systems, a nutrient solution is aerated by the output of an aquarium pump.

Articles referring to Aeration:

  1. N/A

Aerobic

Aerobic literally means “breathing air.” Aerobic is most often used to describe microbes that rely on the presence of air to survive.

Opposite: Anaerobic

Articles referring to Aerobe:

  1. N/A

Aeroponics

A system in which the roots of a plant are consistently or intermittently misted with fine droplets of nutrient solution.

Articles referring to Aeroponics:

  1. N/A

Amino Acids

Amino acids are the basic building blocks of proteins. There are 500 known amino acids, although only 20 are encoded for by DNA. Amino acids contain amine (-NH2) and carboxyl (-COOH) functional groups, along with a side chain (known as an R group) specific to each amino acid.

Articles referring to Amino Acids:

  1. N/A

Anaerobic

Anaerobic literally means “not breathing air.” Anaerobic organisms are almost entirely single-celled organisms, and many are dangerous to animals and humans. Common examples of anaerobic bacteria include Bacillus anthracis (Anthrax) and Clostridium botulinum (Botulism).

Opposite: Aerobic

Articles referring to Anaerobic:

  1. Compost Teas: Taking Fertilizer to the Next Level

Annuals

Annuals are a group of plants that have evolved to grow, flower, produce seeds, and die within a single year. Summer annuals germinate during spring or early summer and mature by autumn of the same year. Winter annuals germinate during the autumn and mature during the spring or summer of the following calendar year. Cannabis is considered to be a summer annual plant.

Articles referring to Annuals:

  1. N/A

Anthocyanins

Anthocyanins are a group of pigments found in plants that appear as red, purple, or blue. They are responsible for the dark purple color found in eggplants. The role of anthocyanins in plants is contended, although most scientists agree that they serve as photoprotectants.

Articles referring to Anthocyanins:

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Aphids

Aphids are a superfamily of insects that suck plant sap. They are extremely common agricultural pests that can be found on the stems and leaves of plants. They reproduce asexually, meaning that a single aphid can become a full-blown infestation. Methods for handling them organically involve the use of essential oils or biopesticides.

Articles referring to Aphids:

  1. Pesticides in Washington
  2. Trimming Services: Save Time and Money

Arc Discharge

A transfer of electricity across two electrodes (anode and cathode), characterized by high electrode current densities and a low voltage drop at the electrode.

Articles referring to Arc Discharge:

  1. N/A

Aspergillus

Aspergillus is a genus of mold species, most of which are capable of reproducing asexually. Various species of Aspergillus are known to cause infection in humans.

Articles referring to Aspergillus:

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B


Bacillus thuringiensis (BT)

Bacillus thuringiensis (BT) is a gram-positive, soil dwelling bacterium. It is most commonly used as a biological pesticide, and is frequently used in organic organic agriculture to manage pests. It is one of more well-known biopesticides and is generally considered safe.

Articles referring to Bacillus thuringiensis:

  1. Pesticides in Washington

Ballast

An auxiliary piece of equipment designed to start and to properly control the flow of power to gas discharge light sources such as fluorescent and high intensity discharge lamps. In metal halide systems, it is composed of the transformer, capacitor and connecting wiring; sodium systems require an ignitor in addition to the transformer and capacitor.

Articles referring to Ballasts:

  1. How to Measure Horticultural Lighting Performance – Part Two

Beneficials

Beneficials are organisms that are considered “beneficial” to horticulture and grow operations. These can include predatory insects such as ladybugs and predatory mites, growth boosters, such as mycorrhizae and soil bacteria, and more.

Articles referring to Beneficials:

  1. Integrated Pest Management
  2. Oregon Consumer Protection
  3. Pesticides in Washington
  4. MedMen – Los Angeles, California

Bifenazate

Bifenazate is a miticide that is considered to have relatively low toxicity. However, bifenazate is registered for non-food use, on top of a lack of an established tolerance for cannabis, making it inappropriate for cannabis usage

Articles referring to Bifenazate:

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Biodynamic Agriculture

Biodynamic Agriculture is an early form of alternative agriculture developed by Rudolf Steiner in 1924. It was one of the first organic agricultural movements. It emphasizes the use of manures and composts and excludes the use of artificial chemicals on soil and plants. However, there are some controversial elements to Biodynamic Agriculture. Rudolf Steiner emphasized taking into account lunar cycles and astrology and the use of various animal body parts in Biodynamic Agriculture.

Articles referring to Biodynamic Agriculture:

  1. Compost Teas: Taking Fertilizer to the Next Level

Biopesticide

A biopesticide (short for biological pesticide) is a living organism that acts in a fashion similar to chemical pesticides. Biopesticides are frequently used in organic agriculture. Examples include Bacillus thuringiensis (BT), ladybugs, and predatory mites.

Articles referring to Biopesticides:

  1. Integrated Pest Management
  2. Pesticides in Washington

Bioponics

Bioponics is a specialized form of hydroponics, focusing on only using organic nutrients in a hydroponic medium. Unlike traditional hydroponics, which can use non-organic nutrients which are readily accessible to plants, bioponics introduces microbes which can break down organic molecules into nutrients into the system. As a result, the process is somewhat more finicky and requires more cleaning, but input costs are lower and the end product is considered to be organic.

Articles referring to Bioponics:

  1. Revolution Cannabis – Chicago Illinois

Black Mold

Black mold is a specific form of mold that produces compounds that are highly toxic to mammals, especially humans. It requires very damp conditions to persist, and does poorly in dry conditions.

Articles referring to Black Mold:

  1. Pesticides in Washington
  2. The Wrong Way to Use Chemicals and Pesticides

Bracts

Bracts are a modified/specialized leaf that can serve a variety of functions, including attracting pollinators, protecting the flower, and more. In cannabis, bracts make up most of the substance and weight of high-quality marijuana buds, and contain some of the highest concentrations of trichomes.

Articles referring to Bracts:

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British Thermal Units (BTU)

The British Thermal Unit (BTU) is a traditional unit of heat; it is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. One watt is approximately 3.41214 BTU per hour. An air conditioning unit measuring one ton is equivalent to 12,000 BTU.

Articles referring to British Thermal Units:

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Brix

Brix levels, commonly just called “Brix”, are a measurement of sugar content in an aqueous solution. One degree Brix is 1 gram of sucrose in 100 grams of a solution. Thus, Brix represents the strength of the solution as a percentage of mass. Brix does not strictly apply to sugar and can be used to measure any amount of dissolved solids in a solution. In the context of cannabis, degrees Brix can be measured in the xylem, phloem, or flower of the plant during different life stages. Higher Brix content means that more nutrients are being delivered around the plant relative to water content. Brix can be measured by comparing the density of the solution to the density of water.

Articles referring to Brix:

  1. Compost Teas: Taking Fertilizer to the Next Level

Broad Mites

Broad mites (species name: Polyphagotarsonemus latus) are a species of mite that cause stunted growth, blackening, and death in plants. At a glance, the damage looks like the kind of damage a plant might experience if exposed to an herbicide. Broad mites prefer places of high humidity and low temperature.

Articles referring to Broad Mites:

  1. Pesticides in Washington

Bud

“Bud,” short for flowerbud, is the part of the cannabis plant containing the highest concentration of cannabinoids.

Articles referring to Buds:

  1. Trimming Services: Save Time and Money
  2. Scrogging: Bringing your Grow into Control
  3. Variations in Cannabinoid Reporting: Part One

Budder

Budder is a type of extract similar to wax. Budder has the consistency of ear wax.

Articles referring to Budder:

  1. The Evolution of Extracts – Part One
  2. The Evolution of Extracts – Part Two
  3. The+Source – Las Vegas, NV

Butane Hash Oil (BHO)

Butane Hash Oil is a kind of extract produced by extracting cannabis flower with butane via a an extractor (can be open or closed). A variety of different concentrates can be made from this base oil, including shatter, wax, live resin, and more.

Articles referring to Butane Hash Oil:

  1. Inside Look at Leading AZ Extraction Company
  2. The Evolution of Extracts – Part One
  3. The Evolution of Extracts – Part Two
  4. Trimming Services: Save Time and Money

C


Calyx

A calyx (plural: calyces) is a part of the flower used to protect the flower while it is budding. It is made up of numerous sepals that surround the outermost layer of the flower. In cannabis, many growers mistake bracts for calyces.

Articles referring to Calyces:

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Canadian Standards Association

The Canadian Standards Association (shortened as CSA) is a nonprofit association serving business, industry, government and consumers in Canada and the global marketplace. Among many other activities, CSA (www.csa.ca) develops standards that enhance public safety.

Articles referring to Canadian Standards Association:

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Candlepower

The luminous intensity of a light source, as expressed in candelas.

Articles referring to Candlepower:

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Cannabichromene (CBC)

Cannabichromene is a non-psychoactive cannabinoid that may have anti-inflammatory, anti-depressent, anti-viral, and/or anti-fungal effects. More research needs to be conducted on this molecule to say for certain.

Articles referring to Cannabichromene:

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Cannabidiol (CBD)

Cannabidiol (CBD) is a non-psychoactive cannabinoid produced after decarboxylating CBDA. Studies show that it appears to be useful as a pain reducer, anti-anxiety medicine, and anti-psychotic.

Articles referring to Cannabidiol (CBD):

  1. Inside Look at Leading AZ Extraction Company
  2. The Grow-Off: Quantitative Competition
  3. Treatise on Decarboxylation – Part One
  4. Treatise on Decarboxylation – Part Two
  5. Establishing an In-House Laboratory
  6. The+Source – Las Vegas, NV

Cannabidiolic Acid (CBDA)

Cannabidiolic Acid (CBDA) is a non-psychoactive cannabinoid that is a precursor to CBD. Evidence suggests that is useful as an anti-inflammatory.

Articles referring to Cannabidiol (CBD):

  1. Treatise on Decarboxylation – Part One
  2. Treatise on Decarboxylation – Part Two

Cannabielsoin (CBE)

Cannabielsoin (CBE) is a non-psychoactive cannabinoid derived from CBD. It is produced metabolism of CBD, or exposure of CBD to the elements. Little else is known about CBE.

Articles referring to Cannabielsoin (CBE):

  1. The Grow-Off: Quantitative Competition

Cannabigerol (CBG)

Cannabigerol (CBG) is a non-psychoactive cannabinoid produced after decarboxylating CBGA. CBG has shown some signs of being useful as an anti-inflammatory agent, and many other properties that have not been completely investigated by scientists.

Articles referring to Cannabigerol (CBG):

  1. Treatise on Decarboxylation – Part Two

Cannabigerolic Acid (CBGA)

Cannabigerolic Acid (CBGA) is the acid precursor to CBG. Currently, it is unknown what, if any, effects it has upon the human body.

Articles referring to Cannabigerolic Acid (CBGA):

  1. Treatise on Decarboxylation – Part Two


Cannabinol (CBN)

Cannabinol (CBN) is a non-psychoactive cannabinoid that is typically found as THC degrades from metabolism or exposure to the elements. CBN has been shown to have analgesic properties.

Articles referring to Cannabinol (CBN):

  1. The Grow-Off: Quantitative Competition

Canopy

The top of a group of plants is known as the “canopy.” When plants are examined from above, the canopy is the top layer of leaves and branches. In general, the canopy of a group of plants is the layer of leaves most exposed to sunlight.

Articles referring to Canopy:

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Carbon Dioxide (CO2)

Carbon Dioxide (CO2) is a molecule that is essential for photosynthesis. Plant stomata regulate the flow of gases, allowing CO2 in, and water vapor out. Currently CO2 only constitutes about 0.041% of the atmosphere, so many growers supplement their grows with CO2 to increase photosynthetic rate.

Articles referring to Carbon Dioxide:

  1. Vapor Pressure Deficit
  2. Scaling Up a Boutique Grow Operation
  3. Revolution Cannabis – Chicago, Illinois
  4. MedMen – Los Angeles, California
  5. VPD for Cannabis Cultivation
  6. Treatise on Decarboxylation – Part One

Carbon Dioxide Oil (CO2 Oil)

Carbon Dioxide Oil (CO2 Oil) is a cannabis extract produced with carbon dioxide under high pressure. Because only carbon dioxide is used, the resulting extract is solvent-free.

Articles referring to Carbon Dioxide Oil (CO2 Oil):

  1. The Evolution of Extracts – Part One

Carotenes

Carotenes are group of plant pigments found in nearly every plant that are responsible for most of the yellows and oranges associated with Fall. Carotenes serve as a supplementary to chlorophyll, aiding in photosynthesis by capturing light energy in different parts of the spectrum.

Articles referring to Carotenes:

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Cation Exchange Capacity (CEC)

Cation Exchange Capacity (CEC) is the total capacity of a soil to hold exchangeable cations. It is a very important soil property influencing soil structure stability, nutrient availability, soil pH and the soil’s reaction to fertilisers and other ameliorants. Cation Exchange Capacity can also be known as media absorption or anion exchange capacity.

The clay mineral and organic matter components of soil have negatively charged sites on their surfaces which adsorb and hold positively charged ions (cations) by electrostatic force. This electrical charge is critical to the supply of nutrients to plants because many nutrients exist as cations (e.g. magnesium, potassium and calcium).

Articles referring to Cation Exchange Capacity:

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Centrifuge

A centrifuge is a device used to separate out particles in a suspension. By rotating at several hundred or thousand revolutions per minute, denser particles will sink to the bottom of a test tube, and the less-dense particles will rise to the top.

Articles referring to Centrifuges:

  1. N/A

Ceramic Metal Halide (CMH) or Light Emitting Ceramic (LEC)

Ceramic Metal Halides (CMH) are a kind of High-Intensity Discharge (HID) bulb that emits light when electricity is passed through a mixture of mercury and metal halides.

Articles referring to Ceramic Metal Halides or Light Emitting Ceramics:

  1. Revolution Enterprises – Chicago, IL
  2. Del-Gro – Coachella, California

Chemigation

Chemigation (an amalgamation of chemical and irrigation) is the application of any chemical, such as nutrients or pesticides, via the irrigation lines for any horticultural application.

Articles referring to Chemigation:

  1. Pesticides in Washington

Chlormequat

Chlormequat is a plant growth regulator that is used to thicken stems. As a PGR, it is considered to be a pesticide. In the USA, use of chlormequat is restricted to ornamental plants only, and is not allowed for use on food crops.

Articles referring to Chlormequat:

  1. Pesticides in Washington

Chlorofluorocarbons (CFCs)

Chlorofluorocarbons (CFCs) are a group of compounds that are often referred to as “Freon.” They were used heavily as refrigerants for early refrigerators and aerosols. CFC’s have been determined to be a primary cause for ozone depletion in the atmosphere.

Articles referring to Chlorofluorocarbons (CFCs):

  1. Integrated Pest Management

Chloroplast

Chloroplasts are cell organelles responsible for photosynthesis. Chloroplasts contains chlorophyll, the pigments responsible for the green color of plants.

Articles referring to Chloroplasts:

  1. N/A

Chlorophyll

Chlorophyll are a group of pigments responsible for the majority of photosynthesis. Chlorophyll absorbs light energy in the blue and red spectrum of light, reflecting green light, which is why we perceive most plants as green. Chlorophylls are found inside of chloroplasts.

Articles referring to Chlorophyll:

  1. Trimming Services: Save Time and Money

Chlorosis

The condition of a sick plant with yellowing leaves due to inadequate formation of chlorophyll. Chlorosis is typically caused by a nutrient deficiency, usually iron or nitrogen; nutrient deficiencies are themselves often caused by a pH that is outside of an acceptable range.

Articles referring to Chlorosis:

  1. N/A

Chromatography

Chromatography is an analytical technique used in chemistry to separate out the constituent components of a sample. Typically, a solvent and sample are mixed and then allowed to travel through an adsorbing material. How the sample travels can be implemented via a variety of different means: gravity, pressure, capillary action, and more.

Articles referring to Chromatography:

  1. N/A

Citric Acid Cycle (CAC)

The Citric Acid Cycle (CAC), also known as the Krebs Cycle, is a set of follow-up reactions to glycolysis in order to produce more ATP. It it usually followed by the Electron Transport Chain (ETC). The exact reactions for the CAC are complicated, but the general process is detailed in the image below, courtesy of Wikipedia:

Articles referring to the Citric Acid Cycle (CAC):

  1. N/A

Cleanroom

A cleanroom is a specialized room designed to be kept free of contaminants. Cleanrooms are useful for laboratory testing companies and as quarantine rooms for new genetics. Some cleanrooms use negative pressure to pull contaminants safely out of the room, while others use positive pressure to keep contaminants out.

Articles referring to Cleanrooms:

  1. N/A

Closed Extraction

Extractions are referred to as “closed” or “closed-loop” when they use a solvent that is contained and recovered. An example would be a butane extractor that recovers or collects any of the butane used during extraction. Closed-loop extractions are generally thought to be safer and more economical, but require more equipment.

Opposite: Open Extraction

Articles referring to Closed Extraction:

  1. Inside Look at Leading AZ Extraction Company

Coconut Coir

Coconut Coir (often shortened to Coco or Coco Coir) is an organic grow medium for hydroponic cultivation or amendment to organic soil, excellent air and moisture retention properties, and harbors beneficial micro-organisms.

Articles referring to Coconut Coir:

  1. Scaling Up a Boutique Grow Operation
  2. MedMen – Los Angeles, California

Coefficient of Utilization (CoE)

The Coefficient of Utilization (CoE) is a measurement of the efficiency of a luminaire in transferring light to the desired plane (IE the canopy).

Articles referring to Coefficient of Utilization (CoE):

  1. How to Measure Horticultural Lighting Performance – Part Three
  2. Scrogging: Bringing your Grow into Control

Cola

In cannabis, a cola is a group of buds that are tightly grouped together. The primary colas of cannabis tend to grow at the top of the plant.

Articles referring to Colas:

  1. Scrogging: Bringing your Grow into Control

Coliform Bacteria

Coliform bacteria are a group of bacteria that are commonly found in most environments which humans occupy. The presence of coliform bacteria is an indicator of the sanitation quality of a particular food or product. E. Coli is one such coliform bacteria.

Articles referring to Coliform Bacteria:

  1. Establishing an In-House Laboratory

Colony Forming Units (CFU)

Colony Forming Units (CFU) are a unit of measurement for microbes. When a microbe or group of microbes is cultured on an agar petri dish, they form a “colony.” These colonies are then counted as CFU.

Articles referring to Colony Forming Units (CFU):

  1. N/A

Compost Tea

Compost teas are a special kind of compost, where traditional compost is taken and mixed with oxygenated, warm water to encourage beneficial bacteria to grow and flourish. Some systems for producing compost tea are as simple as an oxygen bubbler in a bucket, and others are more advanced, producing whirling vortexes. Ideally the water should be saturated with oxygen to prevent any anaerobic organisms from growing.

Articles referring to Compost Tea:

  1. Compost Teas: Taking Fertilizer to the Next Level

Condenser

A condenser is part of a refrigeration unit that condenses a refrigerant such as R-410A from a gas into a liquid, thus cooling the refrigerant. In these cooling systems, a conductive metal is used as a heat exchanger (accepting the refrigerant’s heat), and a motorized fan pulls in cooler outside air to cool the heat exchanger.

Articles referring to Condensers:

  1. N/A

Conformance European

The CE Mark is a requirement for products sold to the European Market. The CE Mark identifies a product as complying with the health and safety requirements spelled out in European legislation (Directives) and is mandatory for equipment operating in the European Union (EU). Once the product has received the CE Mark it can circulate freely throughout the European Union countries.

Articles referring to Conformance European:

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Controller

A controller is an electronic device that responds to certain environmental conditions and performs an action or actions to change the environmental conditions, including activating air conditioning units, humidifiers, dehumidifiers, lighting and more. A controller can vary from simple inputs and outputs to more complicated tasks, including controlling VPD.

Articles referring to Controller:

  1. Vapor Pressure Deficit
  2. Choosing a Cannabis Greenhouse
  3. VPD for Cannabis Cultivation

Conversion Bulb

A bulb of a certain spectrum type (e.g. sodium) specially designed to operate while used in the fixture/ballast of a different type (e.g. metal halide). The most popular conversion bulbs by far are sodium conversion bulbs, which allow one to have the sodium spectrum while still using a metal halide system.

Articles referring to Conversion Bulbs:

  1. N/A

COOH-THC

COOH-THC, short for 11-nor-9-carboxytetrahydrocannabinol, is a metabolite of OH-THC. It is not psychoactive. COOH-THC is the metabolite that marijuana testing kits look for, as it persists in the human body for several weeks.

Articles referring to COOH-THC:

  1. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 2
  2. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 3

Corolla

The corolla of a flowering plant is all the petals of a flower, considered as a single unit. Some corollas have separate petals, and others contain fused petals (creating a tube). In cannabis, the corollas are frequently small and relatively unimportant.

Articles referring to Corollas:

  1. N/A

Correlated Color Temperature (CCT)

Correlated Color Temperature (CCT) is not how hot a lamp is. Color temperature is the relative whiteness of a piece of tungsten steel heated to that temperature in degrees Kelvin (K). HPS has a warm (red) color temperature of around 2700K as compared to MH at 4200K, which has a cool (blue) color temperature. This value is largely irrelevant to plants.

Articles referring to Correlated Color Temperature (CCT):

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Crumble

Crumble is a cannabis extract made from BHO. Crumble is made similarly to shatter, but because it has more impurities in it, it produces a solid that crumbles easily when pressed, hence the name.

Articles referring to Crumble:

  1. Inside Look at Leading AZ Extraction Company
  2. The+Source – Las Vegas, NV

Cryptochrome

Cryptochromes are a class of proteins that are sensitive to blue light, and they can be found in both plants and animals.

Articles referring to Cryptochromes:

  1. N/A

Cubic Feet per Minute (CFM)

Cubic Feet per Minute (CFM) is a measurement of the volume of flow for a liquid or gas. Most growers measure the airflow in their grow operations in CFM and purchase ventilation units based on their CFM.

Articles referring to Cubic Feet per Minute (CFM):

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Cuttings

Cuttings are clones of a plant that are taken by snipping off a small portion of a plant’s branches containing a meristem. They are typically placed under a plastic dome to keep humidity high while roots grow, and roots can be encouraged to grow with IBA.

Articles referring to Cuttings:

  1. Vapor Pressure Deficit
  2. Why Successful Plant Cloning is Important

D


Dabbing

Dabbing is a form of cannabis ingestion that involves the use of a small metal rod (often made of titanium or steel), referred to as a “nail”. The nail is heated up to a high temperature (>350 F) and dipped into an extract to produce a strong smoke.

Articles referring to Dabbing:

  1. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 3

Daily Light Integral (DLI)

The Daily Light Integral (DLI) is the amount of PAR a plant is exposed to over a 24 hour period.

Articles referring to Daily Light Integral (DLI):

  1. How to Measure Horticultural Lighting Performance – Part Two

Daminozide

Daminozide is a plant growth regulator that is used in fruit agriculture to make fruit harvesting easier. As a PGR, it is considered a pesticide. The state of California considers Daminozide to be a “probable carcinogen.”

Articles referring to Daminozide:

  1. Pesticides in Washington

Damping-Off Fungus

Disease that attacks young seedlings and cuttings, causing stems to rot at the base; overwatering is the main cause of damping-off.

Articles referring to Damping-Off Fungus:

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Decarboxylation

Decarboxylation is a chemical process by which CO2 gas is removed from a chemical compound via a reaction. In cannabis, this is typically achieved by heating the raw flower (through smoking or extraction).

Articles referring to Decarboxylation:

  1. Treatise on Decarboxylation – Part One
  2. Treatise on Decarboxylation – Part Two
  3. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 3

Defoliation

Defoliation is a training technique to maximize a cannabis plant’s utilization of light in indoor grows. In indoor grow rooms, most of the lighting comes directly from above, with relatively little light piercing the canopy. By regularly removing the lower leaves on the plant (often called “fan leaves), the plant dedicates more energy and growth to the canopy, where the colas form.

Articles referring to Defoliation:

  1. Scrogging: Bringing your Grow into Control

Dewpoint

The dewpoint is essentially an absolute measurement of the amount of water in the air. The dewpoint indicates the temperature at which your current RH and temperature values will exceed 100% RH and condense out of the air. The further the dewpoint is from the current temperature, the less likely condensation will occur. At 100% humidity, the current temperature and the dewpoint will be the same.

Ex: At a temperature of 80F and 50% RH, the dewpoint is 60F. This means that at 60F, the same amount of water in the air would reach 100% humidity and will condense.

Articles referring to Dewpoint:

  1. Golden Leaf Holdings – Oregon
  2. Ask DryGair: Humidity 101

Diatomaceous Earth

Diatomaceous Earth is a misnomer. It is not actually soil or dirt, but the leftover exoskeletons of microscopic algae (named diatoms). The microscopic skeletons have jagged edges which poke holes in insect exoskeletons, causing them to bleed out and die slowly. It is considered harmless to most vertebrates, such as reptiles, birds, and mammals. It is frequently used as an organic means of pest control.

Articles referring to Diatomaceous Earth:

  1. Revolution Cannabis – Chicago, Illinois

Dientamoeba fragilis

Dientamoeba fragilis, sometimes called parasitic fragilis, is a single-celled species that causes gastrointestinal upset in some people, while having no symptoms in others. However, in immunocompromised patients, fragilis can be quite dangerous.

Articles referring to Dientamoeba fragilis:

  1. Establishing an In-House Laboratory

Distillate

Distillate is a specific type of cannabis extract made by distilling >99% pure THC from cannabis. Distillate is typically used to make edibles or infused products, as it is extremely strong and has virtually no flavor.

Articles referring to Distillate:

  1. Revolution Cannabis – Chicago, Illinois
  2. The Evolution of Extracts – Part One
  3. The+Source – Las Vegas, NV

Drain-to-Waste

A hydroponic system wherein drain water is not recirculated, and is instead sent to a holding tank or a municipal service (AKA the drain). Drain-to-Waste is easier to maintain, but less environmentally friendly and increases nutrient costs.

Articles referring to Drain-to-Waste:

  1. Reef Dispensaries – Arizona and Nevada
  2. The+Source – Las Vegas, NV

Drip Aeration

A hydroponic method wherein air pressure from a small air pump is used to percolate nutrient solution out through a ring of feeder tubing which encircles the plant.

Articles referring to Drip Aeration:

  1. N/A

Drip System

A very efficient watering system that employs a main hose with small water emitters. Water is metered out of the emitters, one drop at a time.

Articles referring to Drip Systems:

  1. Reef Dispensaries – Arizona and Nevada
  2. The+Source – Las Vegas, NV

E


Ebb-and-Flow

A hydroponic system in which the medium, usually aggregate pebbles, is periodically flooded with nutrient solution and then drained again, feeding and aerating the medium and root system. This should happen on established schedule determined by the grower.

Articles referring to Ebb-and-Flow:

  1. N/A

Electrical Conductivity (EC)

Electrical Conductivity (EC) is a measurement of how conductive a soil or medium is. It is measured by units of power over distance. EC can help growers approximate the amount of salts, nutrients, water, and more in the media, and quickly check for any soil issues.

Articles referring to Electrical Conductivity (EC):

  1. Integrated Pest Management
  2. Vapor Pressure Deficit

Electron Transport Chain (ETC)

The electron transport chain (ETC) is a set of reactions occurring within the mitochondria of a eukaryote that produces a large amount of ATP when compared to glycolysis or the citric acid cycle. Oxygen is required for the electron transport chain to work.

Articles referring to the Electron Transport Chain (ETC):

  1. N/A

Endocannabinoid System (ECS)

The endocannabinoid system (ECS) is a network of cannabinoid receptors found within the mammalian brain. The ECS is involved in a variety of physiological processes including appetite, pain-sensation, mood, and memory, and in mediating the psychoactive effects of cannabis.

Two primary endocannabinoid receptors have been identified: CB1 and CB2.

Articles referring to Endocannabinoid System:

  1. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 1
  2. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 2
  3. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 3

Enterobacteria

Enterobacteria are a family of Gram-negative bacteria that includes E. Coli, Salmonella, and Yersinia pestis (Black Plague). Not all enterobacteria are dangerous, but many of the more famous ones are.

Articles referring to Enterobacteria:

  1. Establishing an In-House Laboratory

Enzymes

Enzymes are a specific group of proteins that catalyze reactions, greatly accelerating the time needed for chemical reactions to occur. Enzymes are critical for most of metabolism.

Articles referring to Enzymes:

  1. Oregon Consumer Protection
  2. Pesticides in Washington

Escherichia coli (E. coli)

Escherichia coli (E. coli) is a model organism frequently used by microbiologists for experimentation. Most strains of E. coli are harmless and can be found in human intestines and the environment. However, some variants of E. coli can be hazardous to human health, and have been responsible for food recalls.

Articles referring to Escherichia coli (E. coli):

  1. Establishing an In-House Laboratory

Eukaryotes

Eukaryotes are a group of organisms that include all multicellular organisms such as animals, plants, and fungi. Eukaryotes can also be single-celled organisms. Identifying features of eukaryotes are the presence of organelles in cells, DNA of greater complexity, mitochondria, increased size (compared to prokaryotes), and much more.

Articles referring to Eukaryotes:

  1. N/A

European Red Mites

European Red Mites are a species of mite that are considered major agricultural pests, especially against fruit and flowers. They have a very high rate of reproduction and a wide variety of host plants.

Articles referring to European Red Mites:

  1. N/A

Extracts

Extracts are a concentrated form of cannabis, typically with much higher THC and CBD levels. They can be made via a variety of methods, ranging from older methods such as kief and hash to more modern methods such as BHO and Rosin Presses.

Articles referring to Extracts:

  1. Inside Look at Leading AZ Extraction Company
  2. The Grow-Off: Quantitative Competition
  3. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 1
  4. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 2
  5. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 3
  6. The+Source – Las Vegas, NV

F


Fan Leaves

Fan leaves are a portion of the cannabis plant that are considered the “iconic” cannabis leaves.

Articles referring to Fan Leaves:

  1. Trimming Services: Save Time and Money
  2. Scrogging: Bringing your Grow into Control

Feminized

Cannabis is a plant capable of expressing sexual characteristics of male or female plants. Under the right environmental conditions, it can express both sexes. Most growers seek after female or “feminized” seeds because female cannabis plants produce more bud.

Articles referring to Feminized:

  1. N/A

Fertigation

Fertigation (an amalgamation of Fertilizer and Irrigation) is a process wherein fertilizers or nutrients are applied to a horticultural grow via irrigation lines.

Articles referring to Fertigation:

  1. Pesticides in Washington

FIMming

FIMming (FIM stands for “Fuck I Missed”) is a training technique designed to increase the output of an individual cannabis plant. It works by cutting off the shoot apical meristem about 2/3rds of the way down to the next node. The cutting can be done with scissors or pinching with the fingers. The result is that four new shoot apical meristems will form, instead of one, or two by topping. Once the process is complete, and the new meristems have had time to form new nodes, the process can be repeated.

Articles referring to FIMming:

  1. N/A

Flame Ionization Detection (FID)

Flame Ionization Detection (FID) is a method to detect the presence and concentration of organic molecules by igniting them in a hydrogen flame, and can be used in a GC-MS machine. FID is a relatively simple, cheap, and rugged process, but it has severe limitations as well. It cannot detect inorganic molecules and is not as accurate as other, more powerful detection methods.

Articles referring to Flame Ionization Detection (FID):

  1. N/A

Fluorescent Lamp

A discharge lamp in which a phosphor coating transforms ultraviolet energy into visible light. Fluorescent lamps are good for starting seedlings and rooting cuttings, but do not have enough intensity to sustain aggressive growth in plants in the later stages of life, and are not efficient enough in their conversion of electrical power to lumens of light output.

Articles referring to Fluorescent Lamps:

  1. N/A

Foliar Sprays

Foliar sprays are a supplemental means of providing a plant nutrients if it is showing obvious signs of a deficiency. Plants can absorb the nutrients directly through their stomata. It is not a good long term solution, but can be used to solve short term problems.

Articles referring to Foliar Sprays:

  1. Pesticides in Washington

Footcandle

A standard measurement of light intensity, representing the amount of illuminance on a surface one foot square on which there is a uniformly distributed flux of one lumen. More simply, one footcandle of illuminance is equal to the light emitted by one candle at a distance of one foot.

Articles referring to Footcandles:

  1. How to Measure Horticultural Lighting Performance – Part Two


Footprint

The effective surface area covered by a grow light. If you hang your grow light higher, its footprint will increase but the intensity of light hitting the leaves (luminous flux) will decrease exponentially.

Articles referring to Footprint:

  1. N/A

Fungus

Any of a major group (Fungi) of saprophytic and parasitic spore-producing organisms usually classified as plants that lack chlorophyll and include molds, rusts, mildews, smuts, mushrooms, and yeasts. Common fungal diseases that attack plants are “damping-off,” Botrytis, and powdery mildew.

Articles referring to Fungus:

  1. N/A

Fungus Gnats

Fungus gnat larvae feed on fungus, decaying plant matter, and plant roots in soil. While they are generally not dangerous to fully-grown, mature plants, they can inflict extensive damage to seedlings or clones. Several methods that are used to manage them involve the use of BT, diatomaceous earth, and sand.

Articles referring to Fungus Gnats:

  1. The Wrong Way to Use Chemicals and Pesticides

Fusarium

Fusarium is a genus of fungi widely distributed throughout the soil. Most of the Fusarium genus is harmless to plants and animals. However, there are certain Fusarium species that contain mycotoxins which are dangerous to humans and other animals.

Additionally, there is a species of Fusarium (Fusarium oxysporum) that infects plants and causes wilting, commonly called Fusarium wilting. As a soil-borne pathogen, it is near impossible to eliminate in an outdoor growing situation, and the only solution for outdoor growers is to seek out new land or attempt to improve the soil with a better set of environmental microbes, but there are no guarantees. Fungicides can be used, but many are dangerous to human health and inappropriate for use with cannabis.


Fusarium wilt on cannabis.

For indoor growers, fusarium wilt is often handled by quarantining infected plants and sanitizing rooms and areas where infected plants were found. In extreme cases, infected plants should be destroyed and any medium they were in contact with should be disposed of appropriately. Any pot the infected plants were contained in should be sanitized heavily or disposed of.

In areas where oxysporum is ubiquitous, plants can be bred for resistance to the fungus, but this may cost more time and effort than simply moving.

Articles referring to Fusarium:

  1. N/A

G


Gas Chromatography-Mass Spectrometry (GC-MS)

Gas Chromatography-Mass Spectrometry (GC-MS) is a technique used to analyze the chemical composition of a substance or group of substances in a given sample. Cannabis laboratories use GC-MS machines to identify heavy metals and pesticides in samples. Because GC-MS machines convert samples into a gas via heat, they are not used to identify cannabinoids or terpenes, which decompose rapidly under the heat. Instead, HPLC or standard liquid chromatography machines are used for cannabinoid and terpene content.

Articles referring to Gas Chromatography-Mass Spectrometry (GC-MS):

  1. Establishing an In-House Laboratory

Genetically Modified Organism (GMO)

A genetically modified organism (GMO) is any organism, including plants, bacteria, animals, etc. that has had its genes intentionally manipulated by humans. While carrying a negative connotation in common parlance, GMOs can be extremely helpful. For example, most cotton produced today has been genetically modified to produce more cotton, and the insulin used for Type 1 Diabetes is produced by a genetically modified bacterium.

Articles referring to Genetically Modified Organisms (GMO):

  1. What is DNA? What is a gene? What is a protein?

Genotype

An organism’s genotype is its genetic information contained within its cells’ DNA. A genotype is separate from the organism’s phenotype, which is the set of expressed genes found on an organism.

Articles referring to Genotype:

  1. Establishing an In-House Laboratory

Glucose

Glucose is a simple sugar that is considered to be one of the most important sources of cellular energy.

Articles referring to Glucose:

  1. N/A

Glycolysis

Glycolysis is a set of chemical reactions that splits glucose into pyruvic acid in order to produce ATP, the basic form of cellular energy. Glycolysis can be followed by Citric Acid Cycle (also known as Krebs Cycle) and the Electron Transport Chain to produce even more ATP.

Articles referring to Glycolysis:

  1. N/A

Good Agricultural Practices (GAP)

Good Agricultural Practices (GAP) are specific agricultural practices designed to produce safe, wholesome food. GAP are related to Integrated Farming.

Articles referring to Good Agricultural Processes (GAP):

  1. MedMen – Los Angeles, California

Gray Mold

Gray Mold (species name: Botrytis cinerea) is a necrotrophic fungus that affects many plant species, including cannabis. It leaves a gray, moldy residue. Gray mold prefers humid, warm conditions.

Articles referring to Gray Mold:

  1. Vapor Pressure Deficit

Guard Cells

Guard cells are cells that control the opening and closing of stomata. When filled with water and swollen, the guard cells contract and open the stomata, and when dry and shrunk, the guard cells relax, closing the stomata. This regulates gas exchange, allowing water to leave the plant when the plant is watered, and reducing water loss when the plant is dry. Guard cells also respond to environmental conditions, closing when the air is dry, and opening when the air is humid.

Articles referring to Guard Cells:

  1. N/A

H


Hashish (Hash)

Perhaps one of the oldest and most well-known forms of cannabis extract, hash is produced by freezing cured cannabis and sifting the frozen trichomes to produce kief. The kief is then compressed and heated to produce “bricks”, which is the final form of hash.

Articles referring to Hashish (Hash):

  1. Inside Look at Leading AZ Extraction Company
  2. The Evolution of Extracts – Part One

Harden-Off

To gradually acclimatize a plant to a more harsh environment. A seedling must be hardened-off before planting outdoors.

Articles referring to Harden-Off:

  1. N/A

Heat Pump

A heat pump (abbreviated as H/P) is a device that is used to transfer thermal energy from one location to another. An air conditioning unit is an example of a one-way heat pump. Some heat pumps are capable of transferring heat in either direction. Heat pumps are generally more efficient at generating heat than a simple electrical resistance heater.

Articles referring to Heat Pumps:

  1. Vapor Pressure Deficit

Heat Sink

A heat sink is a device or material that is designed to absorb thermal output from an electronic device in order to keep it from overheating. The thermal energy in the heat sink can then be removed by a variety of different cooling methods. Heat sinks are typically made of materials that conduct heat well, such as copper and other metals.

Articles referring to Heat Sink:

  1. How to Measure Horticultural Lighting Performance – Part Two

“Heavy” Metals

Many states require tests for “heavy” metals, although this is a misnomer. States are actually looking for metals that are considered toxic — particularly arsenic, cadmium, chromium, mercury, and lead. For example, gold (atomic number 79) is heavier than arsenic, cadmium, and chromium, but is not tested for because it is considered non-toxic.

Articles referring to “Heavy” Metals:

  1. Integrated Pest Management
  2. Oregon Consumer Protection
  3. Establishing an In-House Laboratory
  4. Variations in Cannabinoid Reporting: Part One

Heuristics

Heuristics is a form of logical deduction used both in computing and normal logic to discover novel/new information without relying upon a database of existing knowledge. The most basic form of heuristic is “trial and error,” and more advanced versions are rules of thumb or intuition.

Articles referring to Heuristics:

  1. Cannabis Business Security: Physical and Digital

High Intensity Discharge (HID)

High Intensity Discharge, which is a special type of lighting that is much more intense (brighter) than other types of lighting available. An HID lighting system consists of a ballast, reflector, socket and lamp (light bulb).

Articles referring to High Intensity Discharge (HID):

  1. Scaling Up a Boutique Growing Operation
  2. MedMen – Los Angeles, California
  3. How to Measure Horticultural Lighting Performance – Part Two
  4. How to Measure Horticultural Lighting Performance – Part Three
  5. Physics: Fixtures as Lighting Sources

High Pressure Sodium (HPS)

High Pressure Sodium (HPS) is a kind of High-Intensity Discharge (HID) bulb that passes electricity through a mixture of metallic sodium and mercury, producing heat and light (typically in the red spectrum).

Articles referring to High Pressure Sodium:

  1. Scaling Up a Boutique Growing Operation
  2. Reef Dispensaries – Arizona and Nevada
  3. VPD for Cannabis Cultivation
  4. Del-Gro – Coachella, California
  5. Physics: Fixtures as Lighting Sources

High-Performance Liquid Chromatography (HPLC)

High-Performance Liquid Chromatography (HPLC) is a chromatography technique designed to separate, identify, and quantify components in a mixture. A pressurized solvent is passed through a column containing the sample and an adsorbing material. Because every molecule in the sample behaves differently to the adsorbent material, the molecules will separate out as they move through the column.

Once the molecules are separated, they can be identified out via a number of different means, including GC-MS and spectrometry

Articles referring to High Performance Liquid Chromatography:

  1. N/A

Homeostasis

Homeostasis is the process by which an organism regulates its internal conditions out of equilibrium with the environment. As such, it is one of the defining characteristics of life. Metabolism is the set of reactions used to maintain homeostasis.

Articles referring to Homeostasis:

  1. N/A

Humic Acid

Humic Acid is a mixture of acids that is produced by the decomposition of organic matter. It is a significant organic constituent of many bodies of water. Humic acids are insoluble in acidic water. Fulvic acids are derived from humic acids.

Articles referring to Humic Acid:

  1. Oregon Consumer Protection

Hydroponics

Hydroponics, sometimes referred to as aquaponics or soilless agriculture, is a method of cultivating plants different from the conventional method of growing plants in soil. Seeds or clones are placed into a medium to allow them to root, and their roots or the media is exposed to a nutrient solution. There are many different derivations of hydroponics, including nutrient film technique, ebb-and-flow and bioponics.

Articles referring to Hydroponics:

  1. MedMen – Los Angeles, California

Hygrometer

An instrument for measuring relative humidity in the atmosphere.

Articles referring to Hygrometer:

  1. N/A

Hypochlorous Acid

Hypochlorous Acid is a relatively weak acid that is most commonly used as a disinfectant. It shows some usefulness as a pesticides as well.

Articles referring to Hypochlorous Acid:

  1. Pesticides in Washington

I


Illuminance

The density of incident luminous flux on a surface; illuminance is the standard metric for lighting levels, and is measured in lux (lx) or footcandles (fc).

Articles referring to Illuminance:

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Ideal Gas Law

The Ideal Gas Law is a physical law detailing the relationship of temperature, pressure, and volume.

Pressure and volume are inversely proportional and directly proportional to the temperature and the number of molecules, times a constant determined by the chemical properties of the gas in question.

Articles referring to Ideal Gas Law:

  1. Ask DryGair: Humidity 101

Indole-3-butyric acid (IBA)

Indole-3-butyric acid (IBA) is a plant growth regulator that is used to stimulate root growth, particularly in cuttings. Despite being a plant growth regulator, IBA is generally not considered to be a pesticide.

Articles referring to Indole-3-butyric acid (IBA):

  1. Pesticides in Washington

Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a spectrometry technique capable of detecting metals and nonmetals at concentrations of parts per quadrillion (ppq). ICP-MS is useful for detecting heavy metals.

Articles referring to Inductively Coupled Plasma Mass Spectrometry (ICP-MS):

  1. Establishing an In-House Laboratory

Insect Growth Regulators (IGRs)

An Insect Growth Regulator (IGR) is a chemical hormone that alters an insect’s life cycle. Typically, the insect’s life cycle is disrupted, and as such, most IGRs are considered to be pesticides, subject to regulation by the EPA.

Articles referring to Insect Growth Regulators (IGRs):

  1. Pesticides in Washington

Integrated Farming

Integrated farming is a whole-farm, organic management system with the intent of promoting sustainable agriculture. Integrated farming employs Integrated Pest Management, Integrated Crop Management, and other organic best-practices to minimize environmental impact while improving crop yields.

Articles referring to Integrated Farming:

  1. Compost Teas: Taking Fertilizer to the Next Level

Integrated Pest Management (IPM)

Integrated Pest Management (IPM) is defined by the EPA as “an effective and environmentally sensitive approach to pest management that relies on a combination of common-sense practices. IPM programs use current, comprehensive information on the life cycles of pests and their interaction with the environment. This information, in combination with available pest control methods, is used to manage pest damage by the most economical means, and with the least possible hazard to people, property, and the environment.”

Articles referring to Integrated Pest Management:

  1. Integrated Pest Management
  2. Pesticides in Washington
  3. MedMen – Los Angeles, California
  4. Reef Dispensaries – Arizona and Nevada
  5. Del-Gro – Coachella, California
  6. The Wrong Way to Use Chemicals and Pesticides
  7. The+Source – Las Vegas, NV

Intertek Testing Services

ETL is a mark provided by Intertek and ETL Semko. Intertek (www.intertek-etlsemko.com) is a global leader in testing inspection and certification services. They are a Nationally Recognized Testing Laboratory and tests products to UL, CSA and CE standards.

A product bearing the ETL Listed Mark is determined to have met the requirements of prescribed product safety standards. Moreover, the mark indicates that the manufacturer’s production site conforms to a range of compliance measures and is subject to periodic follow-up inspections to verify continued conformance.

An ETL Listed mark with both “us” and “c” identifiers signifies that the product bearing the mark complies with both UL and CSA product safety standards. If it bears just the “us” identifier, it has been tested and deemed compliant to UL. product safety standards only. An ETL Listed mark with a “c” identifier means the product bearing it complies with CSA product safety standards only.

Articles referring to Intertek Testing Services:

  1. N/A

Inverse-Square Law

The Inverse-Square Law is a physical law that states that the concentration of any radiant energy is inversely proportional to the square of the distance from the energy source. In horticultural lighting, this means that light intensity will decrease as distance from the light source increases.

Articles referring to Inverse-Square Law:

  1. How to Measure Horticultural Lighting Performance – Part Two
  2. Physics: Fixtures as Lighting Sources

J


Coming soon…


K


Kief

Kief is a solventless cannabis extract produced by sifting frozen, cured cannabis. The frozen trichomes break off easily from the cured cannabis, leaving a fine yellow powder. This powder is known as kief, and can be used to produce further extracts such as hash. Kief is one of the oldest known cannabis extracts.

Articles referring to Kief:

  1. Trimming Services: Save Time and Money

L


Law of Large Numbers

The “Law of Large Numbers” refers to the fact that any probability, given enough time or chances of occurring (numbers) will tend towards the statistically predicted outcome. The Law of Large Numbers is typically employed by agencies such as insurance companies who serve a large number of clients and want to predict the statistical likelihood they will have to pay out the insurance. This, in turn, can help determine the premiums of the insurance business in order to keep it successful and competitive.

Example: A coin flipped 10 times may flip heads every time. Flip it a thousand more times, and it’s extremely likely that the results will tend to be close to 50% heads and 50% tails, assuming the coin is balanced.

Articles referring to the Law of Large Numbers:

  1. Cannabis Business Insurance

Leaf Curl

Leaf malformation due to overwatering, over fertilization, lack of magnesium, insect or fungus damage or negative tropism.

Articles referring to Leaf Curl:

  1. N/A

Liability

Legal liability is a legal term referring to responsibility for any number of things. Employers are liable for their employees’ safety, for example. A parent is liable for their child. Liability applies not just to the law, but also any contracts a person or business has agreed to.

Articles referring to Liability:

  1. Choosing a Cannabis Greenhouse
  2. Cannabis Business Insurance

Light Deprivation

Because cannabis is an annual plant, it relies on light levels and photoperiod to determine when it is time to switch into flowering mode and produce flower buds. Typically cannabis switches into flowering mode (in outdoor grows) during Fall, as the length of day starts to shorten. In commercial greenhouses and outdoor grows, however, it is more efficient to purposely deprive cannabis of light to trick the plant into flowering than simply waiting for Fall to roll around every year. Light deprivation allows growers to harvest cannabis once every 2-3 months instead of once a year. Special materials, often called “blackout” materials, are sold to block as much sun light as possible. Indoor grows, which already control how much light their systems put out, can simply switch the lights off.

Articles referring to Light Deprivation:

  1. N/A

Light-Energy Harvesting Centers

Light-energy harvesting centers are specific protein subunits of chlorophyll where light energy is collected and transferred to the reaction centers of chlorophyll.

Articles referring to Light-Energy Harvesting Centers:

  1. N/A

Live Resin

Live Resin is a cannabis extract produced by flash freezing the cannabis immediately after harvest. The frozen cannabis is then extracted with butane and the butane is then heated off. The result is a gooey, sap-like resin that has a full terpene profile. Live resin is very highly valued, with prices upwards of $100 per gram.

Articles referring to Live Resin:

  1. Inside Look at Leading AZ Extraction Company
  2. Revolution Cannabis – Chicago, Illinois
  3. The Evolution of Extracts – Part One
  4. The Evolution of Extracts – Part Two

Lloyd’s of London

Lloyd’s of London is a specialty insurance marketplace based in England. It serves as an insurance marketplace for risky, niche, or rare items or businesses that cannot typically find insurance elsewhere. It also acts as a general insurer or reinsurer. For a long time, it was the only insurer willing to work with cannabis businesses.

Articles referring to Lloyd’s of London:

  1. Cannabis Business Insurance

Loam

Loam is a special kind of naturally occurring soil, and is considered ideal for gardening and agricultural uses because it retains nutrients well and retains water while still allowing excess water to drain away. It is composed of about 40–40–20% concentration of sand-silt-clay, respectively. Loam soils generally contain more nutrients, moisture, and humus than sandy soils, have better drainage and infiltration of water and air than silt and clay-rich soils, and are easier to till than clay soils.

Articles referring to Loam:

  1. N/A

Lockout

Lockout is a condition that occurs when a plant cannot absorb nutrients present in the soil. It presents itself like a nutrient deficiency would, but the cause is generally a problem with the soil pH being outside of the acceptable range for a plant.

Articles referring to Lockout:

  1. N/A

Lumen

Lumen is a measurement of light output. It refers to the amount of light emitted by one candle that falls on one square foot of surface located at a distance of one foot from the candle. Traditionally, lumens have been the benchmark of a lamps ability to grow plants; meaning the brighter the lamp the better the plant. However, studies have shown that a broader color spectrum lamp will perform much better than a lamp with high lumen output, especially when it comes to plant growth.

Articles referring to Lumen:

  1. How to Measure Horticultural Lighting Performance – Part Two

Luminaire

A luminaire is a technical term used to refer to electrical light bulbs and electrical light sources. All manner of bulbs, fixtures, and lamps are considered luminaires.

Articles referring to Luminaires:

  1. How to Measure Horticultural Lighting Performance – Part Two
  2. How to Measure Horticultural Lighting Performance – Part Three

Lux

A standard unit of illuminance. One lux is equal to one lumen per square meter.

Articles referring to Lux:

  1. How to Measure Horticultural Lighting Performance – Part Two

M


Macronutrients

The primary nutrients Nitrogen (N), Phosphorus (P), Potassium (K) or the secondary nutrients Magnesium (Mg) and Calcium (Ca).

Articles referring to Macronutrients:

  1. Compost Teas: Taking Fertilizer to the Next Level

Mantrap

A mantrap anything that that can lock a person into one place. This could be a backscatter machine, a foyer, a phone booth, or anything similar.

Articles referring to Mantraps:

  1. Securing Your Cannabis Business: Physically and Digitally

Material Safety Data Sheets (MSDS)

Material Safety Data Sheets (MSDS) are a set of documents intended to accompany any potentially hazardous chemical or group of chemicals. They contain instructions for safe handling of said chemical, how to respond in an emergency situation, and important chemical safety data. State inspectors will ask for your MSDS when they are inspecting a property.

Articles referring to Material Safety Data Sheets (MSDS):

  1. Integrated Pest Management

Medium or Media

The substrate or soilless material which supports the plant and absorbs and releases the nutrient solution in hydroponic horticulture. Different media can come in different forms, such as:

  1. Compressed Mats
  2. Blocks
  3. Bricks
  4. Shreds
  5. Plugs
  6. Beads

Articles referring to Media:

  1. N/A

Mercury Vapor Lamp

The oldest member of the HID family, mercury vapor lamps work by arcing electricity through mercury vapor. While more efficient than incandescent, halogen and fluorescent lamps, mercury vapor lamps have the least efficient lumen-to-watt ratio of the entire HID family. This, combined with an improper color spectrum for horticultural applications, makes mercury vapor lamps a poor choice for a grow light.

Articles referring to Mercury Vapor Lamps:

  1. N/A

Meristem

Meristems are a portion of a plant that contains the bulk of a plant’s stem cells. Meristems are where the majority of plant growth occurs — typically they are found at the ends of a branch or stem. Meristems can also be found in plant root tips.

Articles referring to Meristems:

  1. N/A

Metabolism

Metabolism is defined as “the set of life-sustaining chemical transformations within the cells of living organisms”. Metabolism is one of the defining features of life, and is necessary to maintain homeostasis.

Articles referring to Metabolism:

  1. Vapor Pressure Deficit
  2. VPD for Cannabis Cultivation
  3. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 2
  4. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 3

Metal Halide Lamp

A High-Intensity Discharge lamp in which the light is produced by arcing electricity through a mixture of metal halides. The light produced by metal halide lamps is in the white-blue spectrum, which encourages vegetative growth and “bushiness” while discouraging upward growth. This is the bulb to use in the first, vegetative phase of plant growth. This term is often used interchangeably with Ceramic Metal Halide Lamps, but there are differences between the two.

Articles referring to Metal Halide Lamps:

  1. N/A

Microclimate

A microclimate is a spot within a building or grow operation with a slightly different set of environmental conditions than the rest of the structure. Microclimates can be the result of localized air conditioning units, poor air circulation, or a property of the local environment (IE corner of a room). Growers should try to avoid producing microclimates.

Articles referring to Microclimates:

  1. Choosing a Cannabis Greenhouse

Micronutrients

These are nutrients that plants need only in small amounts. High levels can be toxic. Also referred to as trace elements. Includes Sulfur (S), Iron (Fe), Manganese (Mn), Boron (B), Molybdenum (Mb), Copper (Cu), and more.

Articles referring to Micronutrients:

  1. Compost Teas: Taking Fertilizer to the Next Level

Mini-Split

A mini-split is a special type of heat pump designed for small, enclosed spaces. They are made of two primary components: An outdoor condenser, and an indoor air-handling unit. Several commercially available mini-split systems are designed to be ductless, reducing engineering costs and complexity.

Articles referring to Mini-splits:

  1. N/A

Minimal Risk Pesticides

Minimal risk pesticides (sometimes called section 25b pesticides) are pesticides that have been determined by the EPA to “pose little to no risk to human health or the environment.” These pesticides are important to cannabis, because they are the only pesticides that either have very few or no safety concerns. In the state of Washington, for example, these are some of the only pesticides permitted for use on cannabis.

Ex: Pyrethrins

Articles referring to Minimal Risk Pesticides:

  1. Pesticides in Washington

Mites

A group of arthropods that are typically very small, often microscopic. Their environmental role is diverse — some act as decomposers, others are predatory, and still others are parasitic. The mites that most growers worry about are spider mites, although some growers use predatory mites as a biopesticide.

Articles referring to Minimal Risk Pesticides:

  1. Pesticides in Washington
  2. The Wrong Way to Use Chemicals and Pesticides
  3. The+Source – Las Vegas, NV

Mitochondria

Mitochondria are organelles found within eukaryotes, including humans and cannabis. They are responsible for the majority of cellular energy in eukaryotic cells thanks to their role in the electron transport chain. As is often explained in high school biology: “The mitochondria is the power house of the cell.”

Articles referring to Mitochondria:

  1. N/A


Mosaic Viruses

Mosaic viruses are group of different plant viruses that cause a “mosaic” pattern to appear on plants. The most well-known mosaic virus is Tobacco Mosaic Virus.

Articles referring to Mosaic Viruses:

  1. N/A

Myclobutanil

Myclobutanil is a fungicide. It is considered unsafe for human consumption. It is banned in Canada, Colorado, Washington, and Oregon for the production of cannabis. When it is heated up (particularly via smoking or extraction), it produces a cocktail of dangerous fumes, including carbon monoxide, hydrogen cyanide, and hydrogen chloride.

Articles referring to Myclobutanil:

  1. Oregon Consumer Protection
  2. The Wrong Way to Use Chemicals and Pesticides

Mycorrhizae

Mycorrhizae (plural) are symbiotic relationships between fungal species and plant roots. In this association, the fungus typically inhabits part of the root zone of a plant and supplies nutrients from the soil to the plant in exchange for sugars.

Articles referring to Mycorrhizae:

  1. Oregon Consumer Protection

Mycotoxins

Mycotoxins are a large and diverse group of compounds that are the waste products of fungi. These compounds are toxic to humans and animals.

Articles referring to Mycotoxins:

  1. Integrated Pest Management

N


“Negative Pressure”

When the term “negative pressure” is used, it’s often used to refer to a cleanroom that is pressurized below atmospheric pressure via a ventilation system. As a result, contaminants in the air are prevented from escaping the cleanroom when the doors are opened, and are instead pulled through the ventilation system.

Articles referring to Nutrient Film Technique (NFT):

  1. N/A

Nodes

Nodes are the location of the plant where separate meristems branch off from the main stem. See image below for more detail.


Image courtesy of Wikipedia

Articles referring to Nodes:

  1. Scrogging: Bringing your Grow into Control

Nucleotides

Nucleotides are the monomers that make up DNA and RNA. These consist of Adenine, Cytosine, Guanine, Thymine, and Uracil, often abbreviated as ACGTU.

Articles referring to Nucleotides:

  1. What is DNA? What is a gene? What is a protein?

Nuggets

Nuggets (or nuggs) are dried, cured cannabis buds and colas. They resemble gold nuggets.

Articles referring to Nuggets:

  1. N/A

Nutrient Film Technique (NFT)

A hydroponic method in which nutrient solution is fed into grow tubes or trays in a thin film where the roots draw it up. The nutrient solution flows through the tubes to keep the solution fresh. This “nutrient film” allows the roots to have constant contact with the nutrient and the air layer above at the same time. A downside of nutrient film technique is that it is particularly vulnerable to power outages.

Articles referring to Nutrient Film Technique (NFT):

  1. N/A

Nutrients

The elements needed by plants for normal growth and health. The major nutrients (macronutrients) are nitrogen (N), phosphorus (P), and potassium (K), but there are numerous micronutrients which also have integral roles in maintaining plant health. A good quality hydroponic nutrient formula will contain all of the major nutrients and micronutrients needed by the vast majority of plants.

Articles referring to Nutrients:

  1. Oregon Consumer Protection
  2. VPD for Cannabis Cultivation

O


OH-THC (11-Hydroxy-THC)

OH-THC is a metabolite of THC produced in the human liver after ingestion of THC. OH-THC is psychoactive, and a number of studies have found that OH-THC’s psychoactive effects differ from THC in length, duration, and quality. Additionally, because OH-THC is produced in the liver, its effects on the brain are not felt immediately after ingestion.

Articles referring to OH-THC:

  1. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 1
  2. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 2
  3. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 3

Open Extraction

An extraction is referred to as “open” when the excess solvent is not contained, and is usually lost. When performing a butane extraction, this is done by “blasting” the cannabis with butane without any special equipment. Open extractions are generally less safe because most solvents are flammable, and they cost more money in the long term because excess solvent is lost to the environment.

Opposite: Closed Extractions

Articles referring to Open Extraction:

  1. Inside Look at Leading AZ Extraction Company

Organelle

An organelle, as the name implies, is the cellular equivalent of an organ. It is a region of specialized function found inside of a cell that is contained within a membrane. Organelles can only be found within eukaryotes, and the organelles most relevant to cannabis are chloroplasts.

Articles referring to Organelles:

  1. N/A

Organic (Agriculture)

Organic agriculture is defined by the USDA as “a system that is managed to respond to site-specific conditions.” The goal of the organic program is to improve sustainability, promote better farming practices, and conserve biodiversity. This does not prohibit farmers from using pesticides or chemicals, although generally the pesticides and chemicals must derive from a non-synthetic point of origin.

It is important to note that the word “organic” can be used in many contexts, and is separate from the way chemistry refers to “organic” substances.

Articles referring to Organic (Agriculture):

  1. Integrated Pest Management
  2. Pesticides in Washington

Organic (Chemistry)

In chemistry, an organic molecule is any molecule that contains carbon. This can include pesticides, most things of biological origin, and any synthetic molecules made with carbon. It is important to distinguish organic chemistry from organic agriculture, which is a set of practices intended to promote biodiversity and better farming practices.

Articles referring to Organic (Chemistry):

  1. N/A

Ovule

An ovule is the part of a female flowering plant containing the gametophytes, or female plant reproductive cells. When the ovule is introduced to pollen, the ovule is fertilized and a seed starts to form. In cannabis, two stigmas protrude from a single ovule.

Articles referring to Ovules:

  1. N/A

P


Paclobutrazol

Paclobutrazol is a plant growth regulator that reduces or prevents shoot growth. As a PGR, it is technically considered a pesticide.

Articles referring to Paclobutrazol:

  1. Pesticides in Washington

Pathogenesis

Pathogenesis is defined as a set of conditions that lead to the development of a disease or pest. Many commercial growers try to keep their relative humidity low in order to prevent pathogenesis.

Articles referring to Pathogenesis:

  1. Vapor Pressure Differential
  2. VPD for Cannabis Cultivation

Peat Moss

Peat Moss (genus Sphagnum) is a genus of moss that stores large amounts of water for its size. As such, it is useful to increase water retention as a soil amendment or useful as a growing media.

Articles referring to Peat Moss:

  1. N/A

Perianth

The perianth of a flower is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs. It is made of both the calyx and the corolla. In cannabis, the perianth is relatively small and unimportant.

Articles referring to Perianth:

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Perlite

Sand or volcanic glass which has been expanded by heat; perlite holds water and nutrients on its many irregular surfaces. Perlite can be used as a mineral soil amendment.

Articles referring to Perlite:

  1. N/A

Phenotype

An organism’s phenotype is its set of expressed genes. Phenotype differs from genotype, in that an organism’s genotype is the organism’s entire genetic potential, whereas a phenotype is only the genes that are expressed.

For example, a genotype for a human could indicate that that person could grow to be 7 feet tall, but they never grow beyond 6 feet tall. 6 feet tall is their phenotype.

Articles referring to Phenotype:

  1. Establishing an In-House Laboratory

Phishing

Phishing attacks are a form of cyber attack that target

Articles referring to Phishing:

  1. Cannabis Business Security: Physical and Digital

Phloem

Phloem is a specialized transportation tissue found within plants. Phloem takes sugars and other organic compounds from the leaves and transports them to the rest of the plant. It is is like the veins of a plant. Its counterpart is the xylem.

Articles referring to Phloem:

  1. N/A

Photobleaching

Photobleaching is the loss of color (IE in chlorophyll) caused by overexposure to light. There is sufficient light energy in such situations to break chemical bonds, resulting in gradual color fading. Photobleaching is the reason that old signs and storefronts lose their colors.

Articles referring to Photobleaching:

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Photon

A photon is an elementary particle responsible for light and electromagnetic radiation. Photons always move at the speed of light in a vacuum.

Articles referring to Photon:

  1. How to Measure Horticultural Lighting Performance – Part One
  2. How to Measure Horticultural Lighting Performance – Part Two
  3. How to Measure Horticultural Lighting Performance – Part Three

Photon Efficiency (PE)

Photon Efficiency (PE) refers to how efficient a light source is at converting electricity into PAR photons. A higher PE value means higher electrical efficiency. Photon efficiency is measured in units of µmol/J, or micromoles per Joule.

Articles referring to Photon Efficiency (PE):

  1. How to Measure Horticultural Lighting Performance – Part Three

Photoperiod

Day length; the relationship between the length of light and dark in a 24 hour period.

Articles referring to Photoperiod:

  1. Episode 1: Glass House Farms, CA

Photorespiration

Photorespiration is a reaction that occurs in some plant species when the temperature exceeds the plant’s normal range. Some of the energy produced by photosynthesis is wasted, and the plant’s growth will slow or stall.

Articles referring to Photorespiration:

  1. Vapor Pressure Deficit

Photosynthetically Active Radiation (PAR)

Photosynthetically Active Radiation (abbreviated as PAR) refers to the waveband of light between 400 and 700 nanometers (nm). This waveband correlates very well with the energy of photons that can stimulate photosynthesis in plants, and outside of this range, photons are less or not effective. Thus, this is the waveband used when the amount, or intensity, of photosynthetic light is measured or reported.

Articles referring to Photosynthetically Active Radiation (PAR):

  1. Vapor Pressure Deficit
  2. How to Measure Horticultural Lighting Performance – Part Two
  3. How to Measure Horticultural Lighting Performance – Part Three

Photosynthetic Photon Flux (PPF)

Photosynthetic Photon Flux (PPF) is the amount of PAR photons emitted from a lamp per second. It is measured in micromoles (µmol) per second (s), abbreviated as µmol/s. PPF is a measurement of total photosynthetic light output of light source.

Articles referring to Photosynthetic Photon Flux (PPF):

  1. How to Measure Horticultural Lighting Performance – Part One
  2. How to Measure Horticultural Lighting Performance – Part Two
  3. How to Measure Horticultural Lighting Performance – Part Three

Photosynthetic Photon Flux Density (PPFD)

Photosynthetic Photon Flux Density (PPFD) is the PPF incident upon a square meter with units of or µmol/m2s. In other words, the PPFD is a given PPF over a specific area, such as a canopy. It is a measure of intensity of light in a given area, not a measurement of overall light output.

Articles referring to Photosynthetic Photon Flux Density (PPFD):

  1. Reef Dispensaries – Arizona and Nevada
  2. How to Measure Horticultural Lighting Performance – Part One
  3. How to Measure Horticultural Lighting Performance – Part Two
  4. Physics: Fixtures as Lighting Sources

Phototropin

Phototropins are a set of proteins that mediate the phototropism response in plants.

Articles referring to Phototropism:

  1. N/A

Phototropism

The gravitation of a plant part toward a light source. A series of hormonal reactions in the stems of plants are triggered by light and will cause plant stems to bend towards a light source.

Articles referring to Phototropism:

  1. N/A

Phytochrome

Phytochromes are a class of proteins found in plants that can detect the presence of light. Phytochromes are sensitive to light in the red and far-red spectrum of light.

Articles referring to Photochrome:

  1. N/A

Piggybacking

Piggybacking is a security term used to refer to a hostile agent who quickly follows legitimate business in order to prevent detection. Piggybacking relies on coercion, unlike tailgating.

Articles referring to Piggybacking:

  1. Cannabis Business Security: Physical and Digital

Piperonyl Butoxide (PBO)

Piperonyl Butoxide (PBO) is an organic compound that, while having no pesticidal effect itself, enhances the effects of other pesticides. It was first registered in the USA in the 1950s, and is typically used in combination with pyrethrins. The EPA states that PBO has a low acute toxicity rating, however, they have not analyzed its effects in combination with other pesticides. When heated to decomposition temperature (200 Celsius), it produces an acrid smoke that is toxic.

Articles referring to Piperonyl Butoxide:

  1. The Wrong Way to Use Chemicals and Pesticides

Pistil

The pistil is a part of a female flowering plant that contains all of the female reproductive parts, including the ovules and stigmas.

Articles referring to Pistils:

  1. N/A

Plant Growth Regulators (PGRs)

Plant Growth Regulators (PGRs) are a group of compounds that greatly affect the growth and behavior of plants, much like hormones greatly affect the growth and behavior of animals. There are currently five recognized groups of plant hormones: auxins, gibberellins, cytokinins, abscisic acid (ABA) and ethylene. The EPA defines PGRs as a kind of pesticide, despite not having any pesticidal activity.

Articles referring to Plant Growth Regulators (PGRs):

  1. Integrated Pest Management
  2. Pesticides in Washington

Polymerase Chain Reaction (PCR)

Polymerase Chain Reaction (PCR) is an analytical technique typically used in genetics laboratories. An enzyme (DNA polymerase) is used to make huge numbers of copies of a sample of DNA, allowing a laboratory to amplify any isolated DNA that they find.

Articles referring to Polymerase Chain Reaction (PCR):

  1. Establishing an In-House Laboratory

Polymorphism

A polymorphism is a portion of a species genome that can change from organism to organism. These can be single nucleotide polymorphisms (SNPs) or large sections of the genome.

Articles referring to Polymorphism:

  1. Establishing an In-House Laboratory

Polytunnel

A polytunnel is a special kind of greenhouse structure made out of some form of polymer plastic. Polytunnels are cheap to erect and maintain.

Articles referring to Polytunnel:

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“Positive Pressure”

When the term “positive pressure” is used, it is frequently in association with cleanrooms. Cleanrooms with positive pressure are pressurized above regular atmospheric pressure such that when the doors are opened, airborne contaminants cannot enter the room, as they are pushed out.

Articles referring to Positive Pressure:

  1. N/A

Powdery Mildew

Powdery mildew is a fungal disease that affects many plant species and can be caused by many fungal species. Infected plants display white, powdery spots on leaves and stems. The spots will grow and become denser as the disease progresses. Hot and humid conditions are ideal for the growth of powdery mildew. Powdery mildew can be controlled with careful environment and pest management.

Articles referring to Powdery Mildew:

  1. Integrated Pest Management
  2. Vapor Pressure Deficit
  3. The Wrong Way to Use Chemicals and Pesticides
  4. Establishing an In-House Laboratory
  5. Trimming Services: Save Time and Money
  6. The+Source – Las Vegas, NV
  7. Is Powdery Mildew Systemic?

Power of Hydrogen (pH)

Power of Hydrogen (pH) is a measurement of the acidity of a substance. The scale runs from 0 pH (extremely acidic) to 14 (extremely basic). Pure water, which is neutral, is 7 on the pH scale. Most plants, including cannabis, have an optimal pH range, and anything outside of that range is harmful to the plant. If the pH of the soil falls outside normal ranges for the plant, nutrient lockout may occur.

Articles referring to Power of Hydrogen (pH):

  1. Integrated Pest Management

Propagation

There are two different kinds of propagation: sexual and asexual. Sexual propagation requires pollen to enter the ovaries of a flower and produce a seed. Asexual propagation uses cuttings to make clones of the plant.

Articles referring to Propagation:

  1. N/A

Proteins

Proteins are a large group of molecules produced via protein synthesis. Proteins are made up of long chains of amino acids and are also known as “polypeptides.” Proteins carry out the majority of functions necessary for cells, including as enzymes, cellular signaling, cellular transport, immune response, and more.

Articles referring to Proteins:

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Protein Synthesis

Protein synthesis is the process by which cells make proteins. Proteins are made up of building blocks of amino acids. Protein synthesis can be mediated by organelles and enzymes.

Articles referring to Protein Synthesis:

  1. N/A

Pseudomonas aeruginosa

Pseudomonas aeruginosa is a gram-negative bacterium that is well-known human pathogen, infamous for its resistance to antibiotics.

Articles referring to Pseudomonas aeruginosa:

  1. Establishing an In-House Laboratory

Pyruvic Acid

Pyruvic acid is end product of glycolysis, when glucose is split into two. Pyruvic acid is then either fermented or pushed into the Citric Acid Cycle to produce more cellular energy.

Articles referring to Pyruvic Acid:

  1. N/A

Pythium

Pythium is a genius of “water molds”, which are a fungus-like group of multicellular eukaryotes. Most pythium species are obligate plant parasites (cannot survive without the host), and are frequently transferred to plants via fungus gnats’ feet.

Articles referring to Pythium:

  1. The Wrong Way to Use Chemicals and Pesticides

Pyrethrins

Pyrethrins are a group of insecticidal chemicals derived from chrysanthemums. There is evidence that crushed chrysanthemum seeds were used as an insecticidal agent in China as early as 1000 BC. As one of the oldest and most widely used pesticides in history, it is largely regarded as safe for almost all uses. However, pyrethrins do not persist very long in the environment, and require frequent reapplication for maximum effect.

Articles referring to Pyrethrins:

  1. Pesticides in Washington

Q


Coming soon…


R


R-410A

R-410A is a refrigerant used in air conditioning. It was first created in 1991 by Honeywell and has become the standard refrigerant for many new home air conditioning systems. R-410A (which contains only fluorine) does not contribute to ozone depletion. It is replacing an older refrigerant, R-22.

Articles referring to R-410A:

  1. N/A

Radiant Flux

Radiant flux is the amount of light energy emitted by a luminaire over time. It is measured in Watts (W).

Articles referring to Radiant Flux:

  1. N/A

Re-entry Restrictions

Re-entry restriction is time that a greenhouse or room should be kept closed and should only be entered with proper protective gear. There should be proper signage indicating what’s being sprayed, the strength of the spray, who sprayed, and what time it was sprayed, along with a clear indication of how long you must avoid entry into the area.

In other words, the re-entry restriction is the period of time when no unprotected person should be in the room or handling the plant.

Articles referring to Re-entry Restrictions:

  1. The Wrong Way to Use Chemicals and Pesticides

Red Teaming

Red teaming is a security term used to refer to the act of hiring a “red team” to purposely try and break through your security systems.

Articles referring to Red Teaming:

  1. Cannabis Business Security: Physical and Digital

Reflectivity

The measure of the reflective quality of a surface; the relative ability of a given surface to reflect light away from it without absorbing, diffusing or otherwise compromising the light’s quality, intensity and spectrum.

Articles referring to Reflectivity:

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Reflector

Reflectors are a part of lighting systems designed to focus light towards the intended target. In most lighting systems, reflectors are made of a highly reflective material designed to diffuse light as evenly over the light’s footprint as possible.

Articles referring to Reflectors:

  1. How to Measure Horticultural Lighting Performance – Part Two
  2. Physics: Fixtures as Lighting Sources

Reinsurance

Reinsurance is a special type of insurance wherein the reinsurer acts as an insurance company for another insurance company. The purpose of reinsurance is protect insurers from incidents (IE Natural Disasters) where many claims are made on policies that would otherwise cause the insurance agency to go under.

Articles referring to Reinsurance:

  1. Cannabis Business Insurance

Relative Humidity (RH)

Relative Humidity (RH) is defined as “the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at a given temperature.” It is typically represented as a percentage value, such that 50% RH is equal to 50% of the max water vapor capacity of the air at a given temperature.

Articles referring to Relative Humidity (RH):

  1. Vapor Pressure Deficit
  2. Choosing a Cannabis Greenhouse
  3. Revolution Cannabis – Chicago, Illinois
  4. MedMen – Los Angeles, California
  5. Reef Dispensaries – Arizona and Nevada
  6. VPD for Cannabis Cultivation
  7. Ask DryGair: Humidity 101

Reverse Osmosis (RO)

Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane to remove ions, molecules, and larger particles from water. Reverse osmosis can remove many types of dissolved and suspended species from water, including bacteria, and is used in both industrial processes and the production of potable water.

Articles referring to Reverse Osmosis (RO):

  1. Episode 1: Glass House Farms, CA

Rhizosphere

The rhizosphere is a narrow region of soil directly influenced by a plant’s roots and their secretions. The rhizosphere is where most of a plant’s symbioses with microorganisms take place.

Articles referring to Rhizosphere:

  1. Compost Teas: Taking Fertilizer to the Next Level

Rick Simpson Oil (RSO)

Rick Simpson Oil (RSO) is a kind of extract named after Rick Simpson, the person who popularized the extract. RSO is relatively simple to make, using only some cheesecloth, a liquid solvent (naptha being the traditional solvent), a few containers, and a heat source. RSO can also be referred to as cherry oil or honey oil.

Articles referring to Rick Simpson Oil (RSO):

  1. The Evolution of Extracts – Part One

Rider

A rider is an amendment or addition to an insurance policy that confers additional benefits to the policy holder in exchange for a higher premium. For example, an accidental death and dismemberment policy may carry a rider for death due to human errors.

Articles referring to Riders:

  1. Cannabis Business Insurance

Rockwool

Inert, soilless growing medium consisting of woven, thin strand-like fibers made from molten volcanic rock and limestone, which is heated to over 2900 degrees F, extruded, and formed into slabs, cubes and blocks.

Articles referring to Rockwool:

  1. Reef Dispensaries – Arizona and Nevada

Rosin Press

A Rosin press is a machine used for extraction. By using moderately high temperatures and high pressures, it is possible to “squeeze” out oil and terpenes without using a solvent. Rosin-pressed material can then be used like any other extract, without any of the hassle or side effects of leftover solvent.

Articles referring to Rosin Presses:

  1. Inside Look at Leading AZ Extraction Company
  2. The Evolution of Extracts – Part One

Russet Mites

Russet Mites (Aceria anthocoptes) are a species of mite found in North America and parts of Europe. These mites prefer moderate to cool temperatures, and while their primary host is thistle, they also attack cannabis plants.

Articles referring to Russet Mites:

  1. N/A

S


Salmonella

Salmonella is a genus of bacteria responsible for a wide variety of illnesses, although it primarily causes food poisoning. If Salmonella enters the blood stream, it can cause typhoid fever.

Articles referring to Salmonella:

  1. Establishing an In-House Laboratory

Screen of Green (SCROG)

“Screen of Green” is a training technique similar to “Sea of Green.” In small grows where space is limited and a lighting footprint is small, growers can install netting above the plant canopy to make sure light is distributed evenly between plants. Because of the “screen,’ most individual plants will form multiple colas to attempt to get around the physical blockage.

Advantages: Useful for small grows to maximize harvest times and amounts.
Disadvantages: More seeds/cuttings are required and more attention is required. Tightly packed plants tend to favor pathogenesis.

Articles referring to Screen of Green (SCROG):

  1. MedMen – Los Angeles, California
  2. Episode 1: Glass House Farms, CA
  3. Scrogging: Bringing your Grow into Control

Sea of Green (SOG)

“Sea of Green” is a training technique for cannabis grow rooms that have a limited amount of space. By cramming many plants close together and forcing them to flower early via light deprivation, one can grow and harvest cannabis faster in a smaller space. The downside is that this method doesn’t work well with certain strains and it requires more cuttings or seeds.

Articles referring to Sea of Green (SOG):

  1. N/A

SEER Rating

A SEER Rating, short for Seasonal Energy Efficiency Ratio Rating, measures air conditioning and heat pump cooling efficiency, which is calculated by the cooling output for a typical cooling season divided by the total electric energy input during the same time frame. A higher SEER rating means greater energy efficiency. The minimum SEER rating allowed by the Federal Government is 14.

Articles referring to SEER Ratings:

  1. N/A

Sepals

Sepals are a part of a flower that are used to protect and support the flower petals. A group of sepals acting together is known as a calyx.

Articles referring to Sepals:

  1. N/A

Shatter

Shatter is a cannabis extract produced from BHO. By placing the BHO in a vacuum oven for several hours without agitation, the cannabis extract will develop an ordered, crystalline structure resembling glass. This “glass” shatters easily, hence the name.

Articles referring to Shatter:

  1. Inside Look at Leading AZ Extraction Company
  2. Revolution Cannabis – Chicago Illinois
  3. The Evolution of Extracts – Part One
  4. The Evolution of Extracts – Part Two
  5. The+Source – Las Vegas, NV

Soil Amendments

Soil amendments are products that modify the soil or media in some way. Some possible uses include:

  1. Modifying soil pH
  2. Modifying the ability of soil to retain water.
  3. Fertilizers
  4. Aerators

Articles referring to Soil Amendments:

  1. Pesticides in Washington
  2. Oregon Consumer Protection

Soil Porosity

Soil Porosity is the degree to which soil is permeated with pores or cavities through which water or air can move and is the sum of the water-filled and air-filled porosities.

Articles referring to Soil Porosity:

  1. Pesticides in Washington

Spectral Power Distribution (SPD)

Spectral Power Distribution (SPD) is a measurement of the strength of PPFD per individual wavelength. See diagram below for example.

Articles referring to Spectral Power Distribution (SPD):

  1. N/A

Spectrometry

Mass spectrometry is an analytical technique used in chemistry to identify the constitutent molecules of a substance. By ionizing molecules and then separating them by their mass-charge ratio, the chemical structure of a molecule or group of molecules can be determined.

Articles referring to Spectrometry:

  1. N/A

Spectroradiometer

A spectroradiometer is a device used to measure the spectral power distribution of a luminaire. Spectroradiometers can measure a variety of different attributes of light, including PAR, PPF, and PPFD.

Articles referring to Spectroradiometer:

  1. N/A

Spider Mites

Spider mites are a family of mites that live on the underside of leaves, forming silk webs and puncturing plant leaves in order to feed. In cannabis, if you can see the webs, the plant is generally doomed. They are so small that they are only visible under a magnifying glass or microscope.

Articles referring to Spider Mites:

  1. Del-Gro – Coachella, California
  2. Pesticides in Washington
  3. Integrated Pest Management
  4. Establishing an In-House Laboratory
  5. Trimming Services: Save Time and Money

Spiromesifen

Spiromesifen is a miticide and insecticide designed for use on ornamental crops. It has a relatively low toxicity rating when used as intended, however, it decomposes into carbon monoxide at 300 degrees Celsius.

Articles referring to Spiromesifen:

  1. The Wrong Way to Use Chemicals and Pesticides

Spray Adjuvant

Spray adjuvants are chemicals that are intended to enhance the effectiveness of pesticides and herbicides. By themselves, they have no pesticidal action. Ex: Piperonyl Butoxide

Articles referring to Spray Adjuvants:

  1. Pesticides in Washington

Springtails

Springtails are a group of non-insect arthropods that prefer moist conditions. Different species consume different food sources, but they typically consume decaying matter and occasionally plant matter.

Articles referring to Springtails:

  1. The Wrong Way to Use Chemicals and Pesticides

Standard Operating Procedures (SOPs)

Standard Operating Procedures (SOPs) are a set of standardized step-by-step instructions for employees to carry out routine tasks. There can be SOPs for normal operations as well as uncommon operations (IE Pest Management). SOPs improve communication, standardize the industry, and reduce errors.

Articles referring to Standard Operating Procedures (SOPs):

  1. Integrated Pest Management
  2. The Wrong Way to Use Chemicals and Pesticides
  3. Episode 1: Glass House Farms, CA

Staphylococcus aureus

Staphylococcus aureus (sometimes shortened as “Staph”) is a gram-positive bacterium known for its role in human infections. A well-known form of Staph, MRSA, is resistant to multiple antibiotics.

Articles referring to Staphylococcus aureus:

  1. Establishing an In-House Laboratory

Stigmas

Stigmas are the parts of a female flowering plant that catch pollen for ovules. They are “fuzzy”, usually white, but may be yellowish, or pink to red and, very rarely, lavender to purple. In cannabis, there are two stigmas per ovule.

Articles referring to Stomata:

  1. N/A

Stomata

Stomata (plural of stomate) are pores that can be found on the underside of plant leaves. Stomata are responsible for the majority of gas exchange in a plant leaf. When open, they allow water to escape leaves as a vapor and carbon dioxide and oxygen to enter the plant. Stomata are controlled by cells known as “guard cells.”

Articles referring to Stomata:

  1. Vapor Pressure Deficit
  2. VPD for Cannabis Cultivation

Sugar Leaves

Sugar leaves are smaller leaves found next to cannabis’ colas. Typically they are trimmed off of a flower that is intended to be sold.

Articles referring to Sugar Leaves:

  1. Trimming Services: Save Time and Money

Super-Cropping

Super-Cropping is a training technique that induces growth in a cannabis plant by stressing it gently. By gently pinching and bending the plant’s stems to damage the vascular tissue without destroying it, the plant will grow wider and stronger. If the bent stem is held in place via ziptie or string, it will retain this bent angle. This method helps produce more colas per plant at the expense of space.

Articles referring to Super-Cropping:

  1. Scrogging: Bringing your Grow into Control

Suspension

A suspension is a heterogenous mixture of molecules in a liquid that does not dissolve. The molecules/particles instead are “suspended” in the liquid, and are generally visible to the naked eye.

Articles referring to Suspension:

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Tailgating

Tailgating is a security term used to refer to a hostile agent who quickly follows legitimate business in order to prevent detection. Tailgating relies on deception, unlike piggybacking.

Articles referring to Tailgating:

  1. Cannabis Business Security: Physical and Digital

Tannins

Tannins are a group of molecules that cause proteins to contract and precipitate proteins out of solution. They are responsible for the “puckery” feeling in red wines and certain fruits.

Articles referring to Tannins:

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Terpenes

Terpenes (sometimes shortened to “Terps”) are a diverse group of chemicals responsible for the smells and flavors associated with cannabis. Terpenes are also responsible for the smells and flavors associated with fruits, flowers, and wines. There are a large number of different terpenes, and some of them are suspected of having pharmacological effects.

Articles referring to Terpenes:

  1. The Grow-Off: Quantitative Competition
  2. Revolution Cannabis – Chicago, Illinois
  3. The Evolution of Extracts – Part One
  4. The Evolution of Extracts – Part Two
  5. Variations in Cannabinoid Reporting: Part Two


Tetrahydrocannabinolic Acid (THCA)

Tetrahydrocannabinolic Acid (THCA) is a precursor to THC. When decarboxylated, THCA becomes THC. THCA is known to have a variety of medical uses, including as an anti-inflammatory, neuroprotectant, anti-emetic (prevents vomiting), and anti-cancer (specifically prostate cancer) agent.

Articles referring to Tetrahydrocannabinolic Acid (THCA):

  1. Treatise on Decarboxylation – Part One
  2. Treatise on Decarboxylation – Part Two
  3. Smoking vs. Eating Cannabis: The Effects on Patient Health Pt. 3
  4. Variations in Cannabinoid Reporting: Part One

Thrips

Thrips are an order of insects that typically feeds on plant sap via a proboscis. They also typically act as disease vectors, bringing in a variety of other problems with them. There are over 6,000 identified species of thrips, and they are closely related to aphids and lice.

Articles referring to Thrips:

  1. Integrated Pest Management
  2. Pesticides in Washington
  3. Del-Gro – Coachella, California
  4. The Wrong Way to Use Chemicals and Pesticides

Tolerance (Pesticides)

Pesticides tolerances are the maximum amount of a pesticide allowed to remain in or on a food or consumable item. In the US, tolerances are established by the EPA.

Articles referring to Tolerance (Pesticides):

  1. Pesticides in Washington

Topping

Topping is a training method similar to fimming. By cutting or pinching off the apical meristem, the cannabis plant will produce two primary colas, rather than the normal one.

Articles referring to Topping:

  1. Scrogging: Bringing your Grow into Control

Training

“Training” is a term used to refer to different methods to control or alter plant growth. There are many methods to train a plant, including pruning, topping, and fimming.

Articles referring to Training:

  1. Trimming Services: Save Time and Money
  2. Scrogging: Bringing your Grow into Control

Trichomes

Trichomes (from the Greek for “hair”) are hair-like projections found on many species of plants. In cannabis, the greatest concentration of cannabinoids are typically found within the trichomes emanating off of the flower buds.

Articles referring to Trichomes:

  1. VPD for Cannabis Cultivation
  2. The Evolution of Extracts – Part One
  3. The Evolution of Extracts – Part Two

Trifloxystrobin

Trifloxystrobin is a potent fungicide. The EPA requires a 12 hour re-entry restriction time, and any consumable item to contain less than 0.5 PPM (generally). Exposure to extreme heat can cause Trifloxystrobin to decompose into hydrogen chloride, carbon monoxide, amines, and nitrogen oxides.

Articles referring to Trifloxystrobin:

  1. The Wrong Way to Use Chemicals and Pesticides

Triple Quadrupole Mass Spectrometry (TQMS)

Triple Quadrupole Mass Spectrometry (TQMS, sometimes called “Triple Quad”) is a spectrometry technique that allows for detailed analysis of particles via a rather complex mechanism.

Articles referring to Triple Quadrupole Mass Spectrometry (TQMS):

  1. Establishing an In-House Laboratory

Triticonazole

Triticonazole is a fungicide used on ornamental plants, typically turf grasses. It is considered to be very toxic to humans, and workers must wear very stringent protective wear before application. It is completely unsuitable for use in consumable/food agriculture, including cannabis.

Articles referring to Triticonazole:

  1. The Wrong Way to Use Chemicals and Pesticides

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Underwriter

An underwriter is a person or group of people who write insurance policies and bank contracts guaranteeing the validity of the policies. Without an underwriter’s approval, a policy is not considered valid. Typically underwriters have large sets of data to perform statistical analysis on the probability of different events in order to reduce their risk.

Articles referring to Underwriters:

  1. Cannabis Business Insurance

Underwriters Laboratories (UL)

A private organization which tests and lists electrical (and other) equipment for electrical and fire safety according to recognized UL and other standards. A UL listing is not an indication of overall performance.

Articles referring to Underwriters Laboratories:

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UV-A

UV-A, short for Ultraviolet A, is a specific wavelength of light (between 315–400 nm) that passes through the ozone layer and affects all life exposed to sunlight. Excessive UV-A exposure causes sunburns in humans.

Articles referring to UV-A:

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UV-B

UV-B, short for Ultraviolet B, is a specific wavelength of light (between 280–315 nm) that only partially passes through the ozone layer and affects all life exposed to sunlight. Long-term exposure to UV-B has been strongly associated with skin cancers.

Articles referring to UV-B:

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UV-C

UV-C, short for Ultraviolet C, is a specific wavelength of light (between 100–280 nm) that does not pass through the ozone layer. UV-C is dangerous to humans, and direct exposure is not recommended. UV-C is used in germicidal applications to sanitize items or places.

Articles referring to UV-C:

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Vacuum Oven

A vacuum oven is a machine used in extractions to hasten the purification process. By lowering the pressure and increasing the heat, solvents in cannabis extracts can be removed in a much shorter period of time than letting the extract sit in the open air.

Articles referring to Vacuum Ovens:

  1. Inside Look at Leading AZ Extraction Company
  2. The Evolution of Extracts – Part Two

Vapor Pressure Deficit (VPD)

Vapor Pressure Deficit (VPD) is the theoretical difference in vapor pressure between a leaf surface and the air at a given temperature. In other words, how much does water want to evaporate from a leaf? A high VPD correlates with very dry conditions (low RH), and a low VPD correlates with very wet conditions (high RH)

Articles referring to Vapor Pressure Deficit:

  1. Vapor Pressure Deficit
  2. VPD for Cannabis Cultivation
  3. Episode 1: Glass House Farms, CA
  4. Ask DryGair: Humidity 101
  5. Why Successful Plant Cloning is Important

Variable Frequency Drive (VFD)

A variable frequency drive (VFD) is an electrical device that’s used to control the speed and torque of an air conditioning motor.

Articles referring to Variable Frequency Drive (VFD):

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Vermiculite

Mica which has been processed and expanded by heat. Vermiculite has excellent water-retention qualities and is a good soil amendment and medium for rooting cuttings.

Articles referring to Vermiculite:

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Volatile Organic Compounds (VOCs)

Volatile Organic Compounds (VOCs) are a group of compounds that tend to evaporate quickly when exposed to the air. Terpenes are often considered to be volatile organic compounds.

Articles referring to Volatile Organic Compounds (VOCs):

  1. Inside Look at Leading AZ Extraction Company

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Water Holding Capacity (WHC)

Water holding capacity is the total amount of water a soil can hold at field capacity, which is the maximum amount of water the soil can hold.

Articles referring to Water Holding Capacity:

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Wax

Wax is a cannabis extract produced from BHO. Wax is made by turning BHO into a solid while regularly agitating it to prevent crystals from forming. Wax has the consistency of honeybee wax, thus the name.

Articles referring to Wax:

  1. Inside Look at Leading AZ Extraction Company
  2. The Evolution of Extracts – Part One
  3. The Evolution of Extracts – Part Two
  4. The+Source – Las Vegas, NV

Worm Castings

Worm castings (sometimes called vermicast) are an organic fertilizer produced by earthworm fecal matter. The castings improve soil structure and provide a concentrated form of nutrition for plants.

Articles referring to Worm Castings:

  1. N/A

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Xylem

Xylem are specialized transport tissues found in plants. They transport water and nutrients from the roots of a plant all the way up to the leaves. They are like the arteries of a plant, and the counterpart to xylem is the phloem.

Articles referring to Xylem:

  1. VPD for Cannabis Cultivation

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Coming soon…


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Coming soon…



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About the Author

Hunter Wilson is a community builder with Growers Network. He graduated from the University of Arizona in 2011 with a Masters in Teaching and in 2007 with a Bachelors in Biology.