Should I Use Carbon Filters in My Grow Room?


What is a carbon filter?

Carbon filters are a type of air filter that uses a mineral to catch particles. Usually, carbon filters are cylindrical because they provide the most surface area, and they are added to your tent’s ventilation system.

How do carbon filters work?

Carbon filters are essentially containers filled with activated carbon, which has a lot of small pores that, when air is forced through them, catch scent particles. The carbon is “activated” by giving it an electrical charge similar to static electricity that makes the pores “stickier,” meaning scent molecules are far more likely to be caught as they pass through. The surface area of one gram of activated carbon can reach 3000 square meters so there is a lot of surface area available to catch odor and impurities.

Carbon filters don’t require any extra equipment to set up, you just need to connect it to your ventilation system and turn your fan on. You’ll want to organize your ventilation system to pull air from your tent and through the carbon filter before it exits the ventilation system if your goal is to remove smells emanating from inside the tent.

Why are carbon filters useful?

In theory, carbon filters are not necessary—you can run your grow tent perfectly without ever needing to use one. But during the actual growing process, our experience has been that a lot of indoor gardeners prefer using filters because they help eliminate smells and keep some balance in your separate environments. Even if you can tolerate the smell, your neighbors or family may not.

Should I set up it inside or outside?

Like all parts of growing, when you set up your carbon filter you’ll come to another decision: should you set up the filter inside or outside of the tent? There’s no perfect place, but we recommend placing the filter at the beginning of the ducting route to keep the entire setup inside the grow tent.

There are two main advantages to doing this, one is to prevent the odor from escaping from the grow tent to the greatest extent possible, and the second is that the smell and high-temperature air can be pulled out of the grow tent at the same time through ventilation equipment.

The alternative setup is to have the carbon filter at the end of the ducting route (usually outside of the tent), so you will be pulling air from inside the tent, through the fan, through the ducting, and then forcing it out through the filter. The downside of this setup is that you cannot “prefilter” particles out—carbon filters often come with a fabric prefilter that catches larger particles and keeps them out of your system entirely.

Regardless, if you choose to add a carbon filter to your ventilation system, you’ll notice that you’re required to create negative air pressure (so that air is being removed from the tent) because you’ll need to force the air through the filter at some point, and it does not make sense to filter fresh air into the tent (unless you are growing in some moldy environment). Keep this in mind when setting up your ventilation system, and as always, we recommend that you keep one of your ventilation ports on your tent open to help equalize pressure.

How to set up carbon filters in your grow tent?

setting up carbon filter

Carbon filters are usually hung in the upper space inside the tent. Check out this mini guide to setting up yours:

  1. Choose an exhaust fan with compatible CFM (cubic feet per minute) and duct diameter.
  2. Pass the ducting through the ducting ports on the side of the tent (either side, whichever is convenient for you).
  3. Connect the ducting left inside the tent to the outlet of the fan, and secure it with tape.
  4. Connect the carbon filter to the air inlet of the fan.
  5. Place the full set up in the space above the tent and secure it to the tent frame with tape,  string, a rope ratchet hanger, zip ties, or any way you can.


While carbon filters aren’t required for a tent, they really help with improving the general environment as you continue to grow—it may or may not be something you encounter depending on how you have your space set up but it can make a big improvement in livability.

If you have any questions, please don’t hesitate to reach out to us!

And be sure to check out our other blog posts for useful tips on becoming a great grower!

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