Cannabis plants grown outside don’t need ventilation and are exposed to an array of natural elements, from sunshine to a light breeze to evaporation. Indoor growers must mimic these effects while bearing in mind that air circulates naturally in an outdoor garden. Therefore, all indoor gardens require ventilation to remove the old, warm air and replace it with cool, fresh air. 

Why is indoor ventilation so important? Read on to find out. 

Maintaining CO2 Levels

Plants require outside air because they need carbon dioxide (CO2) to maintain their nutrient cycle. In fact, plants absorb almost all of the available CO2 around its leaves very, very quickly. If this CO2 is not replaced, dead air will form around the plant, which often clogs the stomata and restricts plant growth. But too much CO2 is also harmful, as it is for humans, and can poison your cannabis plants.

Even “sealed” grow rooms that use supplemental CO2 still require the old air to be dumped at the end of every lights-on cycle, and replaced with fresh air. By doing this, growers will help assist the nighttime process where plants absorb oxygen rather than CO2.

A duct fan with proper ducting, such as Fantech’s FKD Series and Revolution Fans can bring air from outside and push it air into the area. For advanced growers who use CO2 emitters (tanks, natural CO2, etc.) circulating CO2 is essential to guarantee quality yields and reduce the chance of excess CO2.

Controlling Humidity

Because plants emit water vapor throughout the day, the humidity levels in your indoor grow room will begin escalating – this can encourage diseases and pests. A proper ventilation system works to remove the moisture by wicking away water that’s been released during transpiration (evaporation of water from plant leaves). Ultimately, this will allow your cannabis plants to absorb more nutrients through their root system, resulting in healthier plants with bigger yields.

Intake fans, such as Fantech’s FKD Series and Revolution Fans help growers create negative pressure or suction, which allow for air exchanges every one to two minutes – helping to maintain optimal humidity levels. Duct fans or vent fans will help push moisture-laden air out of a growing area and level out the relative humidity. Add a charcoal filter, and your indoor grow will be free from odor, dust, harmful water vapor, stale CO2, even pollen particles.

Eliminating Excess Heat

The lights in your grow room will create heat. Most plant species thrive at temperatures between 75°F and 79°F. If the temperature in your grow environment rises above this range, it can hinder photosynthesis. While grow lights might only raise your heat levels slightly, a few degrees can make the difference between a successful run and an unsuccessful one. Ventilation helps eliminate excessive heat in your garden and keep your cannabis plants as healthy as possible.

Oscillating fans help you simulate a light breeze – this will also help indoor growers regulate temperature and humidity. Be sure not to point oscillating fans directly at your plants, but rather, move the air in between your plant canopy and your lights. Above all, an efficient exhaust system is the key to ensuring your air remains as fresh as possible. Adding a high-temp shut off to the lights in case the AC malfunctions can be helpful to the environment. Be sure to match the CFM of your room to the fan and filter when you’re picking out equipment to ensure compatibility. Also make sure the temperature controller doesn’t change drastically between night and day.

Preventing Pests and Diseases

Stagnant air is the ideal breeding ground for pests and diseases. From mold to powdery mildew to mites, if your growing environment is humid, you’re only welcoming these unfavorable issues. By properly circulating your air, you can prevent pests and diseases. For example, many pests prefer to lay their eggs in moist topsoil. So, if you have under canopy ventilation installed to keep the top layer dry, you’re decelerating their ability to reproduce, and these pests will move on to a damper environment.

Remember: the movement of air through your indoor growing facility is just as crucial to your cannabis plants as water and nutrients. But too much ventilation can be detrimental. For this reason, the Garden Rebels team recommends using a thermostatically-controlled fan speed controller like Fantech’s Aeolus controller. This device will monitor your environment and maintain an exact set point eliminating temperature fluctuations. ________________________________________________________________

If you need help setting up the right ventilation system for your grow, contact the Garden Rebels team. We offer on-site consulting and will help you set up your operation and troubleshoot issues so that you can maximize your yield and revenue stream.