Indoor Fan Question

I hope this is a simple question! I have a small grow room in a closet. I think I was told that having a fan blow on your indoor plant will help make it strong. So I’m sure you what I am going to ask. Should I have the fan blowing on the plant all of the time or give the plant a rest as while there is no light?

Not sure about lights off time. I know I leave my fans on. I’ve learned it’s important to have the air circulating and not just directly blowing on one spot of the plant. An oscillating fan accomplishes this. Don’t blast them…think breeze.

all the time air movement

Think of your leaves as a fire in a confined space it consumes all the fuel and air around it very fast and replaces it with smoke. Your leaves consume co2 only in a small bubble around them for this reason much like your fire needs new air to burn your leaves need fresh co2 rich air to thrive. even minor leaf movement accomplishes this so an oscillating which moves air does this simple task. Yes it will also strengthen stalks too but doesn’t need to be very strong to do so.

My question is for time the fan should be on, but thanks for the tip of osculating.

Oscillating is good, and yes the fan that stirs the air around in the room should be on 24/7.

The exhaust fan doesn’t need to be on necessarily at night, the plants don’t really breath with the lights off the same way they do with the lights on, this is why we don’t supplement co2 when the lights are off, and of course you don’t need to extract the heat when the lights are off.

But the air needs to be moving around inside the room all the time, to prevent humid areas from building up and contributing to things like mold and mildew.

However, if humidity – as a whole, in the entire room – rises too high overnight, then you will likely need to keep the exhaust fan on at night as well.

Happy growing,



Thanks MacG! The humidity causing mold and mildew makes sense.

Wow, ok I’m glad I read this blog. I have been running both fan and exhaust 24/7. Now I have the exhaust plugged into my timer. At the least should help with the electric bill! =) But I have a stationary fan. Gonna go get a oscillating fan today. This is such a great forum with such intelligent, experienced folks. It really is a godsend for peps like myself.


I have my exhaust fan thermostatically controlled.
Right now during seedling I’ve set the temps to 80F ON and 76F OFF.

the temp in my grow tent stays between 70 and 76 without any intervention from me. So luckily I don’t have any temp issues to have to control. The only issues I have are with humidity. But seem to control that with a humidifier.