air circulation help

[hells187ryder]

should i have my fan blowing air in or out of my "box" or should i have both?

[lowrydergrower775]

you should have both to always have fresh air passing through your box to your plants

[sweetnug]

If no co2 then you need an intake and an exhaust to take out the hot air. Is better if they are on an atmospheric control. They are not that expensive and very good. They will pay off.

[trillions of atoms]

if you low on money you can make holes for the intake and the exhaust and hook up a fan on one side tow either s-ucking air in, causing it to naturally blow it out the other holes or a fan to blow the air out naturally suc-king it in. it doesnt hurt to have both but when moneys tight a passive system might be for you. heat buildup is the main concern so make sure you have a strong enough fan and big enough vent holes.

[Ekoostik_Hookah]

what TOA said is a great idea.....and would work fine if you are low on money.

yea an intake and exhaust would be ideal.....but if you cant have that.
and you only have one fan...i would say have the fan blowing IN, and on the tops of the plants...in order to cool the plants directly, and to keep them moving.. :)