I am going to build a grow box for use in my attic. I have a ton of mdf and some 2x4s, a 400 w hps and about 15 feet square by 8 foot high attic space to use. I don't want to go crazy up there, maybe like 4 plants at a time. I have been doing research and was thinking of doing a scrog grow. So here are my questions... What would be the optimal size for my growbox? Is going with the scrog (or even lst) method a good idea? And right now (March) the temp is a little cool up there but come the summer months it will definately get a lot hotter. The attic has vents in 2 sides of it for a good crossdraft but how can I control the heat when it gets to be a 95 degree day? Will it be a problem?
Most likely your plants will roast up there. Attics trap heat like a greenhouse, expect the attic to be 10-20 degrees warmer than outside and inside the grow box with lights just add on up from there. It will take serious insulation and air conditioning to combat that.