In many parts across the country in the dead of winter, growers are most likely looking for ways to keep themselves and their plants warm, not cool them down. However, you must make sure you don’t forget to keep your fans running. These unassuming components of a growroom are always necessary for growing indoors, no matter what the weather is doing outside.

From stand-up oscillating fans to smaller clips fans placed in strategic areas, growroom fans provide much-needed air circulation that will improve the health of your plants along with the freshness of your growing space.

Why Are Fans Needed in a Grow Room Year-round?

  • Fans deliver much-needed carbon dioxide and oxygen to plant leaves.
  • Fans help prevent diseases, molds and bacteria that thrive in stagnant, cold air.
  • Fans help with condensation in the growing area.
  • Fans help circulate hot and cold air to eliminate hot or cold spots.
  • Fans help eliminate heat stratification.
  • Fans help make the ventilation system run more efficiently

How Many Fans Are Needed in a Grow Room?

The number of fans you need in your growroom depends on a few factors, such as how big your growing space is, how full it is, and the cubic feet per meter rating of the fans being used.

Determining how many fans you need requires a simple calculation. The size (square footage) of your growing area multiplied by 10 gives you your growroom’s required airflow.

Here’s an example using an 8' x 8' grow space:

8’ x 8’ = 64 sq. ft.

64’ x 10' = 640 cfm

In this example, you will need a fan or a number of fans that gives your room a total of 640 cfm (cubic feet per minute) for proper air circulation.

If your growing area is packed with plants, multiply this number by 1.5:

640 x 1.5 = 960 cfm

In this case, the cfm required bumps up to 960 cfm. The same principle is true if your growing area is only half full, in which case you need less cfm than your baseline suggests, so simply multiply your cfm baseline of 640 by 0.5:

640 x 0.5 = 320 cfm

Where Should Fans Be Located in Relation to My Plants?

Fan placement is likely to depend on available space and open electrical plugs in your growing area. If you need more than one fan, space them out as much as possible. After you have your fans installed, it is important to note their angles.

Have your fans oscillating while angled up towards the ceiling or down towards the floor to help with heat stratification in your growing area. Also, a small fan can go a long way towards pulling all the heat that rises in your growing area and moving it back down towards the plants where you need it to be.

This little trick can help keep your heating costs down because it is not letting hot air go to waste. Fan placement does not have to be permanent. Try out different configurations to find which ones work the best for your area.

How Often Should Fans Run?

It may be tempting to turn off your fans when you turn off your grow lights, but this is not a recommended practice. Fans are relatively cheap to run, so it can be cost-effective to just leave them on at all hours.

Think of it this way, you don’t stop breathing just because you’ve gone to sleep, and the same is true for plants. Although plants are not going through photosynthesis that requires carbon dioxide after the lights are out, they still go through the process of respiration, meaning they still require oxygen. In other words, keep those fans churning 24/7!

Remember, fans are not just there to keep you and your plants cool in the summer, they are necessary year-round and offer a myriad of benefits that will keep your indoor garden healthy and productive.

Fans are also an affordable way of keeping heating costs down when used correctly, so do not put off figuring out your growroom’s fan requirements!