GrowBox How Big?

Im limited to 400hps electronic switchable, had to move the growhut and now I figured Id save some loot and build a growbox out of plywood & 2x4's of course.

Would 4x4x6 be ok, I figure 6ft tall due to the hanging light. I would layer the interior with mylar also.

I read that you should have 55watts per sq.ft. Thanks

50w per square foot is the minimum recommended, shoot for around 70w/sqft and you'll be very pleased with the results, so that'd be a little over 5 sq ft of coverage at 70w/sq ft. With it six feet tall plus about 8 inches for the hood height, plus the ten or so inches to the plant plus the foot or so for the containers, that leaves you with three and a half feet of space, seems workable as long as you keep them small in veg.

How do you plan on regulating temperatures in the box?

Sure, you might want to consider higher if you can. Figure 1' above and below the light and 1' for the pots. That would only leave 3'. Could work but as long as your building it anyway... VV

Entropic so what watts per sq.ft would i have at 4x4x6?

I have hooded 400whps light without the glass or fan (this isnt an issue currently cause they are in a closet holding at 82deg),but i plan on adding both those. I will be able to pump cool air in the box by tapping into my bathroom ceiling fan, (i have a few 4" flanges to add to the box) and just leaving the bathroom fan on and adding a exhust fan in the box. i will just have to try and see where temps hold at.

4ft x 4ft = 16sq ft
400w/16sq ft = 25w sq ft


You could always make it that big and just section off an area, or make a veg/flowering area, vegging with a few cfls or something.

How many plants or how big would be best in 4x4 400w area? Would it be better to make it 3x4 12sqft or would that sacrafice less plants? In know there some stealth cabinet growers on this form here iv seen some nice pics

4x4 you can around 12 plants at max. more or less depending on how big you let the plants get.

sectioning off an area for vegging is a good idea.

so i understud i dnt need MH
my HPS-AGRO 400w is ok?
http://www.hydroponics.eu/product.asp?Id=4960-Easy+Kit+400W+HPS+++Sonlight+AGRO+400W+++Timer