I used 40-watt T10s & T12s for many successful gardens, finally working my way up to a sixteen lamp bank :wtf: ... then, I switched to HPS, and it was like night & day (flourescents don't 'penetrate', no matter how many you run) ... Dutch Pimp is right-on :thumbsup:, go with the high-pressure lamps, don't waste your time & money on fluorescents (for the record, I do much prefer the 48" tubes over the CFLs, if you have the room) ... happy gardening :smokin: