Grow Room Fans and Air Movement

Importance of Air Circulation In a Grow Room

Outdoor-grown cannabis plants can be exposed to a gentle breeze that provides them with necessary wind and air circulation. When growing cannabis indoors, your grow room requires ventilation systems to mimic outdoor conditions. 

Here a few reasons why you need proper air circulation in your grow room:

• Control temperature: High intensity grow lights and other devices in your grow room can have a high heat output, which can affect your crop’s growth. Improving the air flow and ventilation of your space can protect your plants against excess heat with cool temperatures.
• Control humidity: Plant transpiration can produce excess moisture in the form of water vapor in your grow room. Having proper airflow can reduce extra moisture and enable your plants to absorb more water and nutrients through their roots for better growth.
• Control pests: Excess humidity is the perfect breeding ground for mold, white powdery mildew, and insects. Industrial fans can provide your crops with a nice breeze to protect them against these pests.
• Strengthen plants: A steady and slight breeze can produce thicker and sturdier cannabis plant stalks. Stronger stalks can provide support for heavy yields.
• Increase carbon dioxide: During the day, plants absorb carbon dioxide for nutrients. Inadequate ventilation can lower carbon dioxide concentrations and reduce the plant’s growth potential. Proper ventilation can actually improve air quality.

While opening windows and vents can improve ventilation in your indoor space, most growers will need a variety of energy-efficient fans (intake/exhaust and circulatory) to create a constant flow of air in their indoor grow room. 

Grow Room Fan Types

When it comes to setting up the proper air circulation system in your grow room, you have to invest in a variety of grow room fan types.

• Exhaust fan: Exhaust fans pull warm air out of your indoor garden space. Some even come with a fan speed controller that allows you to adjust the speed based on your  environmental needs. 

• Intake fan: An intake fan draws fresh air in from outside to supply your grow room with fresh air..

• Oscillating fan: An oscillating fan moves back and forth, gradually changing the airflow direction throughout the room and creating a breezy environment. 

• Booster fan: A duct fan booster is used to support air circulation through the ducts.

• Ceiling fan: A ceiling fan is the best type of fan to create an even temperature around your grow room. It performs an efficient movement of air by pushing down heat and reducing the temperature difference between the highest and lowest points.

Factors to Consider When Looking for Grow Fans

If you’re serious about providing your grow room with the proper air circulation, you are going to need a few strategically-placed fans around your canopy as well as intake and exhaust fans. Ideally, you want to prioritize the intake and exhaust fan quality over circulating fans.

When looking for grow fans, you must consider the following factors: size, speed control, noise, and ability to adjust based on temperature and humidity.

In our grow room, we set up a Vostermans V-FloFan capable of delivering constant air circulation. The vertical air flow from the fan can efficiently mix the hot air with cold and dry with moist air. It is super easy to install, made of corrosion-resistant materials, quieter than most air circulation fans, and saves you on energy costs.

Correctly Sizing Your Grow Room Fan

The type of fan you choose will depend on the size of your grow room. Pay attention to the cubic feet per minute (CFM) used to measure the airflow of your fan.  

Determine the amount of airflow your grow room needs by figuring out its volume in cubic feet.  Multiply your grow space’s length by width by height. This gives you your minimum CFM needed for your cannabis garden. Keep in mind, your intake fans CFM’s should be slightly lower than the CFM of your exhaust to create negative air pressure in your grow room. 

When determining the right CFM for your space, you will need to account for ducting, carbon filters, and heat-producing devices such as light fixtures and bulbs to determine the correct size of your grow room fan. 

In terms of ducting, the number of bends and their sharpness significantly affects air flow resistance compared to a straight ducting. 

Setting Up Grow Fans

Proper fan placement can provide your plant canopy with a steady breeze, but direct and strong fanning can damage the leaves and stems. Wind burn on leaves can cause them to look like claws. Ensure that the breeze from your fan surrounds the canopy, blowing above and below the plant’s canopy.

When setting up your air circulation fans, look around to see if every part of the canopy is slightly “dancing,” as in, gently shaking and moving around. Walk around your grow room to check for spots with stagnant air or no breeze. Make adjustments on your fan placement to ensure you eliminate hot spots and get proper air circulation. 

Circulation fans that create air movement around the room can be left on all day and night. For best performance, exhaust fans should be connected to environmental controls such as fully integrated systems or humidity and temperature monitors to turn on the fans only when the grow room deviates from its pre-set temperature and humidity points. 

In our grow space, our dehumidifier and AC are mounted on the ceiling. We have it set up so that the dehumidifier goes through the air conditioner and the air conditioner shoots the cold air across the room into the vortex that our V-FloFan creates. The result is fresh cool air being blown throughout the canopy of the plants. 

While our fan is one of the quietest on the market, we invested in isolation dampeners to ensure that any fan movement does not go into the building. 

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