If you were doing a lets say 3.5-4 ft tall box grow with room for 3-4 plants how much lightening would be appropriate? Thanks!
What would be the square footage? (LxW) If you're going for 3-4 plants you'll want at least a 150w hps or 200+ actual watts of CFL.
Yup, like Budderball says. General rule of thumb is 40-50watts / sq. ft. of plant canopy. More helps, within reason. Height of your plant or grow chamber doesn't matter unless you're doing CFL lighting, then side lighting definitely helps.