Grow Room Ventilation Calculator

Our grow room ventilation calculator is just what you need to grow kick ass marijuana plants!

Ventilation is often over looked, but it's vital to healthy plants.

You can jump right into the ventilation calculator by plugging in the volume of your grow op (lxwxh), or you can keep reading to learn about CFM and how fast you should be replacing the air in your garden.

What should a Grow Room CFM be?

CFM - This refers to a number of cubic feet per minute your fan can move the air in a room.

At the minimum, you want to replace the air in your grow room every 3-5 minutes.

But, we recommend every 3 minutes.​

This gives your plants fresh oxygen to work with, while also helping to control the humidity.

So, to replace the air every three minutes, you need your CFM to equal the volume of your grow room divided by 3.


If your grow tent is 2x2x2 it has a volume of 8 feet.

Divide 8 by 3, and you get 2.7—anything less than this and your cannabis plants won't be getting enough fresh air.

Now, this is the bare minimum, and many growers opt for every 3 minutes all the way to 3-5 times PER minute.

Also, keep in mind that if you're using a carbon filter you'll need about 20% more power to pull the correct amount of air through your garden.

Your lights can also effect your required CFM too.​


Now, obviously, there is a lot more to grow room ventalation than we talked about here.

And if you want to know more, our guide on cannabis ventilation will help give you a better understanding of why your plants need fresh air as well as tips to getting proper ventilation in your grow room.

So, did our grow room ventilation calculator help you create the perfect environment for your plants?

If you loved it, let us know in the comments below!

Tony Hand

Founder & Editor-in-Chief of If he's not smoking or watching anime, you can find him yelling at over play calling.

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