How to Optimize Airflow in Controlled Environment Agriculture

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In controlled environment agriculture — a broad term that encompasses both indoor grow settings and greenhouse environments — there are a number of key environmental factors that can make or break your yield. All too often, people make the mistake of underestimating one of those factors: airflow.

Higher Yields Consulting How to Optimize Airflow in Controlled Environment Agriculture

Anders Peterson, Cannabis Operations Specialist at Pipp Horticulture, explains that airflow has a huge impact on plant growth, yield, and revenue. Without it, the grow environment suffers from microclimates — that is, inconsistencies in the room’s atmosphere — and other issues that can harm your crop. 

Read on to learn about the importance of good airflow in controlled environment agriculture and how to optimize your facility’s airflow system to avoid microclimates and increase your yield.

Why Airflow Matters

Airflow is one of nine cardinal parameters of plant growth identified by Utah State University professor and researcher Dr. Bruce Bugbee. In terms of indoor controlled environment agriculture, these nine parameters must be engineered to facilitate healthy and robust plant growth indoors. 

While each parameter is important, airflow is the equalizer that balances and harmonizes other factors and processes both within the room and within the plant itself. According to Peterson, airflow directly impacts plant growth by:

  • Facilitating gas exchange: Through the process of photosynthesis, plants take in carbon dioxide and give out oxygen and water vapor. Without airflow, this gas exchange can’t take place effectively. 
  • Preventing microclimates: In the absence of good airflow, microclimates form and improper vapor pressure deficit conditions commence. This prevents plants from taking up as much carbon dioxide, thereby stunting growth and decreasing yield. 
  • Maintaining cooler leaf temperature: Similar to humans sweating, leaves transpire by releasing water vapor through the stomata to cool themselves. Without proper airflow, this process slows down — and so does growth. 
  • Controlling pathogens and pests: Not only does airflow make it more difficult for pests to attach themselves to the plants, but it also decreases plants’ susceptibility to things like mold, mildew, and other pathogens.
  • Mixing and homogenizing the room: Proper airflow helps maintain an even, controlled environment throughout the entire room. This gives you a more uniform crop and helps maximize your yields across your facility. 

Too often, airflow is treated as an afterthought in controlled environment agriculture like cannabis grow facilities. But when ignored, it can cost you a significant amount of your potential yield. 

Controlling Airflow to Avoid Microclimates

Ultimately, airflow’s role in controlled environment agriculture boils down to energy balance. For that energy balance to work, all the components of healthy airflow must work together. Peterson describes it as a recirculating loop, of which half is the HVAC system and the other half is the in-rack fans stationed throughout the room.

The HVAC system cools, heats, dehumidifies, and sterilizes the air before pushing it out into the room. From there, it’s up to the fans in the room to circulate the air into the plant canopy and then return it to the HVAC system to begin the process again. 

Higher Yields Consulting How to Optimize Airflow in Controlled Environment Agriculture

“Airflow is a key factor in this energy balance, which allows the plant to utilize all these other growth parameters to their maximum,” Peterson explains. “If you don’t have good airflow and fan layout in your room, the carbon dioxide-enriched, dehumidified, cooled air won’t get everywhere, and you’ll have microclimates.” 

That’s why no matter how good your HVAC system and ductwork are, if your fans, racks, lights, and other infrastructure components aren’t designed to optimize airflow, you won’t be getting the most out of your grow.

Optimizing Airflow in Controlled Environment Agriculture

To optimize your airflow, Peterson says an important first step is to quantify it. “People say, that’s not enough airflow, or that’s too much airflow, but they don’t put a number to it,” he explains. There are several tools and measurements you can use to quantify your airflow, such as:

  • Hot wire anemometer: Measures the velocity of airflow within the plant canopy.
  • IR thermometer: Measures leaf temperature for an indirect assessment of how even the airflow is.
  • Energy balance equations: Calculate exactly how much airflow you need to balance the energy of your crop based on its temperature, humidity, etc.

Another factor to keep in mind when trying to optimize your airflow is whether you’re working with top-down or bottom-up airflow systems. While both types have their pros and cons, Peterson recommends top-down systems, which tend to present fewer challenges in terms of installation, design, and day-to-day workflow. 

Keep in mind that the level of airflow needed changes as the plants age and receive greater quantities of light. More light causes the plants to transpire at a faster rate, so they need more airflow to maintain the energy balance.

Finally, remember: In controlled environment agriculture, balance is key. Too little airflow causes the leaves to become soggy and stop growing. Too much airflow, however, dries them out with wind stress — which also stops growth. 

Better Airflow for Better Growth

Airflow may seem like only one piece of the controlled environment agriculture puzzle, but it’s a very delicate piece that you can’t afford to get wrong. Otherwise, you risk lower yields, stunted plant growth, and significant revenue loss. 

In Peterson’s words, “The common cultivator just wants to see the leaves dancing. That’s their qualitative assessment of whether they have enough airflow. But in today’s day and age, this market is way too competitive to be leaving an important factor of plant growth like airflow up to ‘Are my leaves dancing or not?’” 

Grow facilities aren’t cheap to build — so don’t cut corners on yours. Protect your investment by working with experts to get your airflow system right the first time.

Contact us today to get a custom grow design for better airflow and maximum yield.

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