Grow tent ventilation question

[piggygrower9969]

Hello,

New grower here . I have a 2x4 grow tent equipped with an exhaust system and fan. I've seen in some videos that I need to keep a "window" open at the bottom of the tent to promote air circulation. But this is somehow counter-intuitive for me, because as far as I understand, the plants need complete darkness during their lights off period in order to avoid stressing them.

So, what should I do? Is it okay to leave a window open, or is it pointless?

Thanks

[OldManGrower]

If you have a commercial tent, there is a bottom flap that can be held open. Yes you need to have a source of intake for fresh air to equal the out flow created by the fan. As far as lighting is concerned, you can shield the opening by putting it close to a wall. I have the essentially the same set up in my garage. The intake flap is a few inches away from the wall and the sides are shielded by shelves. I regularly turn the lights on in the garage and have never had a problem.

[Gingerbeard]

It's a good question because I had the same one. My solution was to duct-tape a towel to the inside of the tent, over the vent. Hanging over the vent, like. Not taped all around.
I started with the same size tent you have. When your tent is closed, and your light is off, a muffin fan is plenty for exhaust. They are also good to fit in small spaces.

[golfnrl]

You need the air circulation. If you have an opening in the bottom of your tent stick a short piece of flex duct on it, make sure it has a bend. The bend will take care of light issues. Or set your tent close to the wall as OldManGrower suggested. It's the light spectrum that you need to be cautious of when your tent is in the dark period. For me, I have a 4x4 photo tent, that's the one with the duct. Also have a 3x3 auto tent, that's the one closest to the wall (5"). They're in the same room. Never have light issues.

[piggygrower9969]

Thank you guys for the answers. Very inspiring golfnrl.

[Jebidiah]

I get filters for window AC units and trim them to size, use magnets to hold them over the screen of the tent. They can be washed clean between grows when the tent gets cleaned.