Growing plants indoors can be extremely fun and rewarding, giving you almost complete control over the inputs your plants receive. But with great power over every variable in your grow environment, comes great responsibility for keeping them at optimal levels. One of the most important aspects of an indoor grow, which also happens to be one of the most overlooked, is air quality.
It's easy to translate the concepts of ample lighting, water and nutrition from an outdoor garden to your indoor space. If your plant doesn't have enough nitrogen or your water's pH is too high, you'll suffer similar effects. When you're outdoors though, there's no lack of ample air flow or air exchange. Plants breathe freely. And while certain temperatures and humidity levels may not be ideal for your plants, in an outdoor setting you just don't have much control over those variables.
As you transition to an indoor space, you have much more control over air quality, along with the risk that not controlling it properly will have direct negative impacts on the growth of your plants. For example, without proper ventilation, it's easy for a grow tent with a high intensity discharge light to rapidly exceed 100 degrees Fahrenheit and remain there for hours on-end.
Here are 5 products that we recommend to improve the air quality in your grow and give you complete control:
Intake and Exhaust Fans
Plants require carbon dioxide (CO2) in the air to perform photosynthesis and grow. As they use up this CO2, they expel oxygen (O2) as a biproduct. Wherever you choose to put your plants, be sure that the air is "exchanged" frequently enough to keep an ample supply of CO2-rich air in the environment. If you're growing in a closed room or tent, you typically want to fully replace the air in your space once every 1-3 minutes.
Check out our grow tip on choosing the proper size of fan for your space:
Now that you're exchanging the air in your grow space, it's time to think about keeping the bad stuff out. Carbon filters can be installed between the external environment and your intake fan to keep pests and pathogens out of the incoming air. Additionally, they can be used between your internal environment and your exhaust fan to prevent unwanted odors from escaping.
Ducting and Hose Clamps
Connecting your fans and filters to your grow space can be easily accomplished with a few feet of ducting and hose clamps to hold it in place. Keep in mind that every inch of ducting and every bend in that ducting has an impact on rate at which your intake and exhaust fans move air through your grow space. Try to keep the length and number of bends to a minimum so that you maximize the efficiency of your fans.
Even with an environment where old air is being exchanged for clean, fresh air every 1-3 minutes, some portions of your grow may still remain stagnant. An oscillating fan will help circulate fresh air throughout the room to ensure it reaches all areas of your plants. Continuous air movement will help keep humidity levels down and reduce the risk of mold, mildew and pest buildup. If you have young plants, a gentle breeze can also assist in building stronger stems and branches just as they would in an outdoor garden where they would need to contend with the natural wind.
Humidifier and/or Dehumidifier
In most cases, humidity can be controlled with proper air exchange and circulation, especially if your grow space is inside a home or building that already has central heating and air conditioning. If your grow is large enough or in a space that doesn't have it's own system, you may need to utilize a humidifier or dehumidifier to add or remove moisture from the air. More often than not, the issue growers run into is levels of humidity that are too high because of the water being used to feed plants and transpiration that occurs when water evaporates from the leaves, stems and flowers.
Check out our grow tip on keeping humidity under control: