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In this lesson, Cameron discusses nutrients and watering procedures for your Cannabis operation.
Hey everybody, it’s Cameron and today we’re going to be talking about nutrients.
Commercial facilities these days are going to need to look at ways to lower costs of goods sold. One of the easiest ways to do that is through the elimination of using liquid-based macronutrient fertilizers.
When you’re thinking about moving away from liquid based fertilizers, you definitely want to be thinking about dry, granular, micronized macronutrients. You can get these in single part” grow” and “bloom” formulas. You can also mix your own. You can but constituent parts. You can buy your nitrogen, your phosphorus, your potassium, and all your micros in single parts and actually build your own recipe to mimic the formula you might be using from one of the major liquid nutrients manufacturers that you’ve used in the past.
While it’s possible to to omit liquid based macro nutrients from your program, you’re still going to want to use liquid based additives. You will generally want to use one or two additives for each phase of life, starting in propagation with a root based formula, and then generally at least one or two on the veg side and one or two on the flower side. In addition to the cycle specific additives you will also always want to be thinking about a Cal-Mag as well as a silica which are going to be used over most parts of most of the life cycle.
So when it comes to mixing your nutrients you’re going to want to mix your nutrients in a specific order so you don’t get nutrient lockout. Often times if you mix your nutrients in the wrong order you can lock out some of the nutrients and they will become unavailable to your plants. So the order you want to mix your nutrients in is as follows: you want to go with your silica first, you want to follow it Cal-Mag, then you want to follow it with your macros and your micros, then your additives, then you want to pH.
Most large scale cultivators are looking for ways to create continuity of their final product. Many of these producers might have licenses in different municipalities, perhaps in different states, and maybe even in different countries. One way to mitigate some of the risk associated with your nutrient program is to start with RO water. RO water is basically like starting at zero. Starting at zero gives you a baseline to start in any facility no matter where you happen to be located. This is the kind of thing that if you are growing let’s say your flagship strain, and you want to have an end result that looks the same in California that it does in Florida that it does in Canada that it does in Switzerland, RO water is the way to do that.
When you decide to use something other than RO water, please be aware that it can fluctuate over time and I would definitely recommend if you’re not using RO water get your water tested at least once a year, and I would probably recommend at least once every six months. You can just Google and find a water testing lab that’s local, they’re going provide a bottle for you to take your water sample in, it’s probably going to take about a week, and it’s probably going to cost you 100-150 bucks ($).
To create uniformity and continuity in your system you want to remove the human element. Most large scale cultivation facilities have done this by creating an automated watering and irrigation system. It removes some of the human element and some of the variability that can come from mixing by hand. You know, this guy is going to mix differently than this guy, and again what we’re trying to create here is continuity throughout the system in this facility and in all of my other facilities, and one way to do that is through an automated system. These automated systems are great. They can give you automated alerts with regards to fluctuations of PPM (parts-per-million), pH. They can also do other things like keep track of the temperature and humidity in the room, so automated systems are definitely the way to go.
One of things we haven’t touched on yet is the progressive nature of the PPM level throughout the lifecycle of the plant. Generally, I like to start below 500, let’s say in the 250-500 range PPMs in the very early, early vegetative stage, and as we go through vegetative and into late flower stages we’re going to progress through the thousands and maybe end around 1400 or 1500 PPMs on the flower side. Generally, my veg cycle runs between 500 to about 1000 PPMs and generally my flower cycle runs from about 1000-1500 PPM.
One of things to be mindful of is nutrient lockout and salt buildup in your media, and the best way to mitigate this problem is to flush your media at least once a month. I prefer once every 2 weeks. This is going to help with nutrient lockout and is going to keep your plants running at their fullest.
When assessing symptoms in your plants, frequently there are symptoms that look similar to other symptoms, and sometimes you will have multiple symptoms on a given plant or on multiple plants on the same table. When you start to get symptoms that look like many different things, it is generally a problem of nutrient lockout. So if you’ve set up a flushing schedule that occurs once a month or once every to weeks, but you’re noticing this in between that schedule the best thing you could possibly do is go right back to flushing and reset and try to get back to zero and start back up again.
When it comes to nutrients and watering the best thing to remember is that a small plant is obviously going to consume less both in terms of volume and in terms of concentration than a much largest plant. The sort of end of the flower cycle, the biggest plant, let’s work backward from there, the biggest plant let’s say that’s taking a gallon a day. So as we move backward from this plant that’s in say week 6, week 7, week 8 of flower, as we move backward we are consuming a lower concentration of PPM and we’re also consuming a smaller volume of water, so a plant that’s let’s say transitioning from veg to flower is probably consuming about half that in terms of volume and about two-thirds that in terms of concentration. Such that a plant that’s in transition is probably consuming about 2000 ml a day and is probably running at about 1000 PPMs.
My preferred method, rockwool, poses some interesting challenges. Although I’ve already advised against hand watering, hand watering with rockwool, it’s basically impossible given the number of times that you would actually need to water. You’re looking at a gallon of water over the day, but you’re talking about increments of 250-500 ml per watering. So you could be looking at watering somewhere between eight and sixteen times a day with rockwool and you can imagine how much labor that would require to do let’s say 1000 plants in a given room, you’ve got five rooms in the facility, it’s basically cost prohibitive and impossible. When it comes to container gardens, you are probably still talking about the same volume of water but much less frequency because the water retention is going to be so much different than with rockwool. So that large plant in a large container, still probably about a gallon a day, but you’re only probably going to do it once a day.
Another thing to remember when it comes to watering is it is directly related to what the external environment is like because what the external environment is like affects the internal environment, so in a place like Maryland in the winter where it’s very cold and rainy, you are going to probably have to water less and a smaller volume. Whereas if you’re in the California desert in July, you’re going to have to water a lot more. There is sort of a trial and error element to this that you’re going to have to bear in mind as you’re progressing through the seasons and when you move from one location to another location. Even within the same facility with the same media and the same plants you could be looking at a 25% or more swing in the total volume that you have to feed from December to July.
So if you liked learning about nutrients, please feel free to refer to our course notes, and also please stay tuned for our next section.
Condition Profile: Nitrogen Deficiency
Condition Profile: Nutrient Burn
Artificial Intelligence is the Latest in Greenhouse Automation Technology
Testing Your Runoff
Drain or Reclaim?
Micronutrients: Pt 1
Micronutrients: Pt 2
Enter code GNU-Student for 10% at Growershouse.
(Excludes “Killer Deal” items)
White Royal Vegetative Base Nutrients – Key Grow Solutions
Canna Cannazym Specialty Nutrient
Botanicare Cal-Mag Plus
Mammoth P – Nutrient Liberator
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