Inline fan/humidity

Hello fellow growers,

I have read optimal humidity during vegetative growth is between 60% and 70% RH. There is a humidifier running, and I have an inline fan set up in the grow room. When running the fan in the low position, humidity drops to 40%RH. Is the exhaust fan only necessary while flowering.

Any help or suggestions would be much appreciated.

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The exhaust fan is important for many reasons, one of which is to control air flow and proper c02 is getting to your plants. 40%rh isn’t bad for veg alot of people run that. If your plants are smaller right now you could put a dome over them to help hold moisture

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Depending on the size of your grow space and the amount of CFM your fan can move(even at its lowest setting) will cause this problem. If you have a 2’x4’x6’ space( 48 cubic ft) and you have an exhaust fan that can move 220 CFM (110 CFM on lowest setting), you end up exchange the air 2-3 times per minute and nothing you add into that room will stay long enough to do anything.

I would turn your exhaust fan into an intake fan to your room (only during veg) and have an exhaust port/or hole at the lower section ( 2”-3” hole) of your grow space. The humidity will always rise upward before falling downward. Let me know if this helps you?

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Thank you!

Thank you, I will try this out!

I actually have a small intake fan at the bottom, I will just reverse my setup while in veg.

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No worries bud, happy to help. If you need any help calculating exhaust and intake, let me know. I can at least get your clothes to watch your intake and exhaust equate to.