The Grow Awards 2026 🏆

Inline Fan Run Time

DonnieRedBuck
DonnieRedBuckstarted grow question 4y ago
Question about exhaust. Never grown indoors before. If temp and humidity are spot on and I have circulating fans on when lights on, do I need to run inline exhaust 24/7? I open the door daily to get come co2 in there. Inline Fan is 203 cfm. Tent 2x2x4. It cools the tent fast.
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Setup. Ventilation
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LoganatorDude
LoganatorDudeanswered grow question 4y ago
Yeah these answers seem spot on. Just remember, there normally is very low levels of CO2 in the air, unless there is a nearby contributor. So if you don’t replace old air before it gets old, then air inside the tent can very easily dip bellow a minimum threshold in co2 levels to sustain normal growth. Just keeping the ventilation on the lowest setting as a bare minimum for tent ventilation, can make a dramatic improvement.
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GrowCN
GrowCNanswered grow question 4y ago
I run a air circulation fan inside the tent continuously to keep the air moving. I use AC Infinity exhaust fans with temperature and humidity control. The exhaust fans only run when needed to maintain temperature and humidity.
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DonnieRedBuck
DonnieRedBuckanswered grow question 4y ago
Thank you everyone!!
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Chow_13
Chow_13answered grow question 4y ago
If you have a fully sealed space and run CO2 then no exhaust. If you have a tent I recommend at least a little exhaust to keep a negative pressure in the tent to keeps smell under control.
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psuperman
psupermananswered grow question 4y ago
I would run it 24/7. I had a plant die recently and after considering the factors and other plants surviving I honestly believe my air circulation was a factor in the grow tent with both intake and exhaust and how often I was running them.
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Cheeba_Inu
Cheeba_Inuanswered grow question 4y ago
I run it 24/7. If it's not needed for reducing heat or humidity I keep it on its lowest speed setting. The reason for that is that plants will grow best with a little bit of air circulation/flow. Plants did not evolve in an indoor setting, and constantly release humidity and gases during transpiration. Airflow strengthens stems and allows leaves to transpire more effectively. If you are running a closed system with added CO2 or have lots of circulation within the tent already that changes things and I can give advice based on those kinds of setups. If your extraction fan does not have adjustable speeds, then the idea of running it on a timer is a possible solution. Happy growing! 🌱👍
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Ezzjaybruh
Ezzjaybruhanswered grow question 4y ago
You do need to get fresh air up in there, and often. Just found out the other day that plants will put off ethylene and if you don’t move air out it can become slightly toxic to plants and only takes a few hours to build up levels they won’t like. Maybe set a timer to run it on intervals?
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