Humidity in cannabis cultivation

Cannabis in the modern era is grown in completely controlled spaces, constantly monitored and adjusted, in order to maintain a consistent quality of product, while attempting to maximize yields.

by Rom Meir

This highly technologized world of cannabis cultivation emerged from the underground indoor growing operations of the pre-legal world, converging with the tight regulations and requirements of pharmaceutical manufacturing. Justified by the end-product's high value, cannabis is able to take the lead at the forefront of agritech.

The new generation of agriculture focuses heavily on creating the right climate conditions for a single crop, and when it comes to cannabis, one very important parameter to keep an eye out for is humidity.

Importance of humidity
Plants are picky, and though they may grow in a relatively wide array of conditions, they do have optimal points, maximizing their growth and quality potential. Just as with temperatures and lighting, humidity is felt by plants, causing them to adjust accordingly, in order to survive. These optimal conditions are based on a crop's evolutionary traits, genetics and origins.

Humidity is one of the leading factors affecting the nutrient cycle of a plant, as it affects the rate of water transpiration from the leaves. When humidity levels are high, transpiration is slowed, causing the plant to take in less water from the roots, water which contains the nutrients needed to grow.

It is important to understand what relative humidity is – the degree of saturation of water contained in the air. When relative humidity is at 100%, the air can't contain any more water vapor, causing water to condense. This is a factor of both the amount of water vapor and the temperature. Colder air can contain less water than warmer air. So, relative humidity will rise either when the amount of water vapor is increased, or when temperatures drop.

This causes condensation, water vapor manifesting itself as a liquid, to occur on the coldest surfaces in the environment. Most commonly being metal objects and infrastructure, such as pipes, railings and vents, as well the plants themselves, which tend to be cooler than the air surrounding them.

Humidity related diseases
Climate control is great for providing crops with the best opportunity to reach their maximum potential. But that's not all. There are other living organisms lurking in a growing facility, and they too have preferred conditions. We’re talking bacteria, pests, and most importantly, in the case of cannabis, molds. The biggest culprit being Botrytis, commonly referred to as bud rot, a fungus which thrives in high relative humidity levels, and could potentially decimate an entire crop cycle, if left unchecked.

The first condition necessary for bud rot to appear in the growing space is free water. Even one small area being too humid or cold, could cause condensation and allow bud rot to appear. Once a single breakout occurs, the fungus creates spores, which can spread through the air, eventually reaching the entire growing space.

Controlling relative humidity is, in fact, controlling the outbreak of disease, with no need for pesticides and fungicides, leading to a cleaner crop, fit for medical consumption.

Cannabis' humidity susceptibility
Cannabis is a special case when it comes to humidity, due to its unique physiology. The dense buds make it much harder for air to pass through, creating a high risk of humidity building up within them. These small pockets of humid air are caused by the transpiration which occurs, without an outlet. Being both cooler and moist, the bud is at extreme risk of condensation occurring inside it, which could potentially bring upon molds, rendering the bud unusable.

With condensation being a real risk, the desired level of relative humidity needs to be kept at a safe distance from saturation.

Energy efficiency
Humidity has long been a factor in agriculture. Though mostly associated with temperature related issues, the effects of humidity have always been felt, but are only now gaining much deserved attention. When it comes to cannabis growing, the methods of coping with humidity vary greatly, the only commonality being the fact that dealing with it is a necessity.

The most important parameter to consider when shopping for dehumidification equipment is the efficiency, with the most straightforward way of being the ratio of water removal to energy consumption, or even better, water removal to cost ratio.

Cutting edge growing facilities
Bringing in new technologies to a growing facility holds the potential to provide additional benefits beyond their sole intended purpose.

A new dehumidifier, in addition to simply reducing moisture, may cut energy costs by as much as 50%, when compared to traditional heat and vent methods. Proper refrigerant based units collect the water removed from the air, potentially providing over 100 gallons of distilled water in a single night.

Another major factor to consider when introducing dehumidification, is how they integrate into the air movement scheme in the space. As an additional piece of equipment which takes in and expels air, it could be utilized to improve the air circulation. Few Technologies emphasize this issue, being specially designed to circulate air in order to homogenize conditions throughout the facility.

When bringing in any new technology, make sure to take full advantage of the opportunity to expand on additional aspects, which may not necessarily be readily apparent.

Economically efficient
Growing cannabis, like any other business, is about the bottom line. The objective, or at least the basic condition of remaining in operation, is to be profitable. The cannabis market, still in its early stages, is changing rapidly. Some of these changes may soon bring about critical shifts to the economic viability of cannabis cultivation.

The major factor allowing cannabis to be grown in such costly operations is the consumer price. With legalization, medically or recreationally, spreading around the world, the price of this formerly illegal commodity, is due to drop. In Colorado for instance, the cannabis market price benchmark has dropped 13% from 2016 to 2017. This trend, coupled with fluctuating energy prices, water scarcity, and growing focus on land use, will eventually force growers to become more efficient in order to remain in business.

Dehumidification technologies are proven to reduce energy consumption, while increasing crop quality and uniformity. In the path to improving performance and profitability, dehumidification is an excellent first step and future staple of any such operation.

For more information:
Rom Meir
DryGair Energies Ltd
8 Hamanofim St, Herzliya
T: +972-9-7730989

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