6x26w cfls is what i use. be careful though. i dont care what ppl say you can burn the shit outta your plans with them. i killed 2 plants last year with them and they were 2" away. 3-4" is perfect unless you have GREAT ventilation blowing directly over the plants and bulbs, then move them closer. Get yourself some socket adapters and some y splitters from home depot or lowes. they work great for me. if you can go with HID's, but you can do a lot with cfls.