You need an exhaust, high on the upper part of your box, which should be 6 feet tall by the way. Then you need an intake, which should be low on the box, and at LEAST as large, preferably somewhat larger, than the exhaust hole.
Next, you need a good fan/blower. You can save a few bucks now by buying just a plain fan and mickeymousing it together with duct tape and baling wire, but in the long run, you WILL be buying a real blower that can move over 150CFM through 4" or 6" ducting. A good blower will run you about $150 and it is worth every penny in increased yields, fewer problems, and less hassle of setup. I resisted the blower for years and finally got one... it has changed my life! lol!
Exhaust fans run most efficiently when they are SUCKING air. Put your fan at the end of the exhaust ducting, outside the box if that is an option (the fan itself makes some heat). Then if you run a carbon filter, put it on the output side of the blower to help muffle the sound, as well as hiding the stank.
stinkyattic Reviewed by stinkyattic on . HELP!! With a small grow box So I about as new as it gets to this growing thing, and I have to say its quite overwhelming, now i see why everyone isn't doing it. So I plan on growing the minimum which I found is usualy around 4 plants to increase the chances of a female. I would like to build my own box. Other than the box it self(wood, screws,some coating for the inside... all that) I plan on getting 1 600W HPS light w/ at least 45,000 lumens. I would like to use a hydro growing technique but it seems like its more costly Rating: 5