Growers Network Staff

August 14, 2018 5 min read
August 14, 2018
5 min read

Humidity in Cannabis Production, Pt. 2

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DryGair’s writing team explains how dehumidification systems save you money on equipment and maintenance, and also protect you from pestilence.

The DryGair Writing Team
Hadar Fuchs-Rubal | Yanor Yazma | Rom Meir

The following is an article produced by a contributing author. Growers Network does not endorse nor evaluate the claims of our contributors, nor do they influence our editorial process. We thank our contributors for their time and effort so we can continue our exclusive Growers Spotlight service.

Cannabis’ medical use, regulations, and high wholesale price have catapulted the industry to the forefront of agriculture and agritech. If there’s one thing that canna-cultivation is teaching the farming world, it’s that every parameter in a grow operation can be completely controlled.

This brings us to a fairly new technology rising in the agritech world – dehumidification.

Humidity is a Key Factor

Relative humidity is like air temperature, plants have a preferred range in which they thrive and ranges which inhibit growth.

But crops aren’t the only living organism in a grow-op. There are pests, bacteria, and fungi lurking, waiting to stake their claim. In the case of cannabis, the most notorious is Botrytis, commonly known as “bud rot”, a fungus dreaded by growers. It also happens to love humidity. In fact, it absolutely needs high levels of relative humidity or it won’t develop at all.

Humidity related ailments are especially critical when it comes to cannabis, particularly because of its end use as a medicine. As such, it requires high levels of scrutiny to maintain quality and uniformity. But it also faces challenges due to its physiological nature. Cannabis buds are extremely dense, running the risk of creating microclimates within themselves. Combine this density with the fact that the plant is constantly transpiring through its leaves, even the sugar leaves on the bud, and we’ve created a humidity monster.

Dehumidification Does it All

Diseases & Crop Loss vs. Quality & Quantity

Controlling humidity levels in a grow operation is critical to fend off bud rot, as well as other common diseases such as powdery and downy mildew. But humidity isn’t all about diseases either — it’s also about giving the plant what it needs at the right time so that we can get more out of it. Good humidity control not only increase a single plant’s growth rate, but also affects the crop placement density, allowing for more plants in a given area.

It all comes down to a simple concept known for millennia – give the plant what it needs and you can get more out of it.

Pesticides & Fungicides

Reducing crop loss through dehumidification is one side of a two-sided coin. The other side is pesticide and fungicide usage. These are a big deal in cannabis because, as we mentioned, it is scrutinized for its medicinal value. Many pesticides are expensive, and they sound really unappealing to consumers. Additionally, many of these pesticides are not rated for use on cannabis, and may turn into even worse chemicals when burned for inhalation.

A simple way to reduce the use of these chemicals is by keeping harmful disease levels low in the first place via smart dehumidification protocols. We’ve discussed this elaborately in a previous article titled “Using Climate Control to Prevent Disease“. If you’re interested in IPM (Integrated Pest Management), which you probably should be, this is for you.

In short, diseases are caused by organisms, all of which have their favorite environmental conditions. When they are deprived of those conditions, they simply don’t actualize into full-blown diseases.

Energy Efficiency & Savings

This is a big deal. In a traditional greenhouse setting, humidity is dealt with by ventilation. It sounds simple and inexpensive, but it’s actually the opposite. Ventilation takes the controlled greenhouse air, adjusted to be just right for the crop, and literally throws it out the window. Needless to say, this wastes precious energy and money. In a modern cannabis grow space, this technique has been swapped out for a different, but more effective method based on the same approach.

HVAC systems are used to control temperatures, and many growers also use them to regulate humidity, because that is a side effect of their function. But most HVAC units are not designed for the task of dehumidification and they’re inefficient at it, to say the least. Running an oversized and overpowered HVAC system to control humidity ends up wasting a lot of energy and, in the long run, unnecessarily wastes money on maintenance in addition to the relatively high initial investment. A dedicated dehumidifier frees up your HVAC system to do what it does best.

Water Consumption

Water is a major component in any agriculture. It is constantly flowing through the environment — including the plants, the soil, and the air. 98% of the water the plant uses ends up back in the air as humidity. Wasting water is exactly that – a waste. Refrigeration-based dehumidifiers, such as those produced by DryGair, can reclaim that water and put it back to work. Needless to say, this is a money saver. With the state of water these days, especially in places like the popular valleys of California, it may, in the near future, become a necessity to be as efficient as possible with this valuable resource.

Related Article: Water regulations in states such as California will likely impact grows. A good dehumidification system combined with a purification system will reduce water usage and waste while also keeping your grow healthy. Check out this article on the subject by Hydrologic.

Next Level Dehumidification

We’ve established that dehumidification alone is worth pursuing. But introducing a new piece of equipment to an operation presents additional opportunities, and here at DryGair, we recognize that.

A key factor in cannabis production is air flow: a constant breeze diffuses the humidity surrounding the plants and prevents the formation of microclimates. This function can actually be integrated into a dehumidification system. We designed our systems to be placed in the center of the grow space, amongst the foliage, in order to create air circulation that evens out with the airflow while it intakes humid air and expels dry air. It’s a twofer.

Uniformity is the holy grail when it comes to air control. Growers work very hard to keep conditions optimal, but one small area, unreached by a fan or poorly insulated, could muck things up really quickly. That’s all it takes for bud rot to take hold in one plant. The spores from that single plant can then get blown around throughout the operation, spreading the infection. It’s the equivalent of how a single child with the flu can get the entire school sick. All that hard work is undone in an instant.

All About Economics

Factoring in all these elements: saving money on energy, water, and pesticides on one hand and increasing efficiency, output, and quality on the other, and the end result is a positive ROI (return on investment) in less than a few cycles. Ask any financial advisor and they’ll tell you that an ROI of less than a few years is almost always a no brainer.

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About the Authors

DryGair’s writers include a team of experienced engineers, agronomists, and economists. They specialize in climate control in closed growing facilities and practical solutions for effective climate management.