For cannabis growers, designing an efficient grow house with environmental controls that are conducive to growing plants indoors can be a tricky science – one that can impact a grower’s yield.
Understanding how to design a grow house with a balanced environment in mind goes a long way toward keeping pests, rot and powdery mildew at bay, maximizing efficiency and, ultimately, profits.
That said, what goes into designing a well-balanced grow room that maintains just the right humidity throughout the grow?
We asked Anden product specialist Randy Lenz to touch on the matter to help better understand the benefits of a grow house designed specifically for cannabis growth efficiency.
When designing a new grow house, what are the first questions you ask yourself and then the customer to make sure you’re on the same page?
First, we ask about the size of the space and what kind of space it is. Are we talking about a greenhouse, a pod, or a sectioned off room with panels in it?
Then, we take a look at the air conditioning equipment already installed. Typically, growers talk in tonnage, so they’ll say, “we have 20 tons, 50 tons, 100 tons of A/C.” Understanding this helps us get a sense for the cooling power within the grow house.
Next, we need to know the number of lights being used to simulate the sun, a necessary part of growing plants indoors. As a rule of thumb, we try to size off of lighting because growers typically optimize the amount of plants they grow per light.
Lastly, we need to know the maximum number of plants the grower plans to cultivate along with how much they plan to water them each day. This helps us determine how much humidity per plant is going to be released into the environment for our units to manage.
How can a poorly designed grow house affect the quality and health of the cannabis product itself?
A lot of it is strain-dependent. Certain strains need certain temperatures and humidity levels. Either way, to produce large quantities of cannabis, you need proper humidity controls. If the moisture is too high, your risk of powdery mildew and bud rot skyrocket. If the moisture is too low, you risk drying out your crop before it’s ready to harvest.
One thing to consider is your plants’ vapor pressure deficit. Basically, when the vapor pressure of a plant is 100% and the leaves and buds are at about 100% saturation, we want that plant to off-gas that moisture so that it can continue to drink more water from the soil where the nutrients are. For example, if you have a dryer environment outside the plant, then the moisture within the plant will decrease and escape out into the environment.
If we can keep our vapor pressure deficit at a good ratio, the plants will transpire more, drink more, and feed more from the nutrient-rich soil, which will give you the best product in the end.
When is it most crucial for a grower to balance his or her growing environment?
Always! A grow needs continuously balanced humidity throughout the growing process, which we know has differing requirements throughout each grow stage.
However, on even a micro level, it’s important to balance humidity throughout specific parts of the day, especially into the night as the lights go off – which is typically when the plants dump moisture from their leaves and start to sweat. You’ll then get water beads on the plant as they’re off-gassing all their CO2, which needs to be removed to protect the plant from moisture damage.
As I always say, it’s like when somebody’s riding a bike or running. They may not be sweating very much initially, but as soon as they stop, everything expels out of them. A plant’s the same way, so we have to get that excess moisture out of there as the lack of light in a nighttime environment affect the way the plant produces moisture. That’s where the biggest problem is with humidity control – getting the moisture out of the air so that the plant doesn’t suffer at night.
From an engineering standpoint, how do Anden products simplify the way growers balance their environments, ensuring optimal vapor pressure deficit night and day?
We install sensors and multiple controls around the room so we can see when the humidity spikes. This allows growers to take action – using their system’s precision controls or even remotely through a corresponding smartphone app – pulling that moisture down before it causes any damage to their crops.
Anden dehumidifiers are all built to include top-end, high-quality components from the compressor to the coil. One of the key components in any refrigerant system is the metering device – something that floods the refrigerant into the dehumidifier.
There are devices that have a constant flow of refrigerants, and there are devices that will regulate the amount of refrigerants used. One of the devices that uses a consistent flow of refrigerant is called a capillary tube system. As an analogy, it’s like having your foot on the gas pedal at the same ration at all times – whether you’re going uphill or downhill, it never changes. You wouldn’t do that. You want to regulate your speed.
The system we use in our large capacity dehumidifiers is called a TXV, a thermostatically controlled expansion valve. This supplies refrigerant based on demand, so when it’s higher humidity and warmer temperatures, you want more refrigerant in the system to maximize your dehumidifiers’ moisture removal. As temperatures dive down, you want less refrigerant to maximize your dehumidifiers’ performance without having coil freeze ups.
If you’re not getting your capacity needs out of your current systems, you want to have a dehumidifier that is designed to work over a wide range of temperatures instead of one that’s specifically designed to work at 80° with 60% humidity – the industry standard for smaller, portable dehumidifier units. However, if you start to fall from that temperature and humidity, maybe 75° with 55% humidity, just dropping five degrees and five percent relative humidity, you’ll see that the capacity of dehumidifiers will start to drop off.
We’ve tested some of our competitors’ units and found up to a 25% drop in capacity with that small temperature and humidity drop.
When you’re looking for a dehumidifier, look to see how the refrigerant is controlled going into the unit, which are grow-optimized to work under a variety of conditions and still get maximum pints per day removal efficiency.