Growtent Question....

... I have a 4x3 growtent. And there are MJ plants inside. they are currently in a 12 day 12 night period. For the 12 hours of dark do I close all the air vents and turn off the fan thats inside of it. Or do I leave the air flaps open during 12 hours of darkness. And what about the fan does it need to run during the dark period?

thank you for taking the time to read this.

I always just kept them on for circulation. They still need to breathe fresh co2 when it's dark.

Yes, I run 24-7. You may want to rig something to prevent light from getting through the intake openings. I used to use a bud lite box with some heavy screen over it. But now use a ducting elbow.

i run 1/2 of my fans during dark period (not the ones cooling the light). I just black carbon pre-filter to block light and add additional filtration. I leave 1-2 intake ports and 1 exhaust port going though the carbon filter.