I would say the 4' x 4' x 2' is possible. From the top of my cooltube (400w hps) to the bottom of my pots (15L) is 41", but I used LST and Scrog to control the height of the plants. You could also look into super cropping, topping, fimming, all kinds of methods to keep your plants short and even higher yields.

My temps are also a little higher than optimal, but still within range... You really need a good fan, and by good I mean it should be able to handle enough heat from the light in the cooltube so you can pull the air out with the fan, instead of pushing it through the cooltube. Then you can hook up your carbon filter to the other side of the cooltube. The second link in my sig goes through all the ways I've been trying to get things to run smoothly, and I finally got it how I want it.
bigtopsfinn Reviewed by bigtopsfinn on . New Grower Needs Help! I just decided to start growing. I bought a 400w MH/HPS light on ebay. I am going to build a wood box in my closet. I was thinking of making it 4' x 4' x 2' but i am not really sure. I could go up to 5 x 5 x 2 but the 4 x 4 box would be easier to build. What i need help with is making an ideal setup with these parameters. Do i have to much light for that space? I know those lights get pretty hot and need to be a certain height above the plant but don't really know how much. Do i fix the lamp up Rating: 5