Hey bro
3 x 3 would fit one plant vegged and trained for 2 months, or you could fit two plants with less veg time.
I'd use 200w minimum. I'm not an LED hater or anything but I usually see better results from HPS.....(You're gonna hear this a lot)
Good luck on your venture
This guy is right . HPS are still the king of the crop . BUT if you are going to buy an led , research it . alot . And whatever you do , especailly since they are still the new kids on the block , DO NOT buy a cheap set . Youll get crap led's , and hate yourself . That much I do know . I have a buddy who spent a fortune on an led setup , and well , it kinda does pretty good , and really looks cool doing it . I dont remember the brand , but dont buy that stupid UFO thing or the chinese EBAY knockoffs either . He went that route and wasted good money .
If your not sure , after research , go with the HPS . Then , depending on your game , if you make a few extra bucks along the way , play a little , or even better , see what your local hydro shop might be doing with them , if they are .