There's probably some major growers that would cringe at it but I just used your basic Merical Grow 24-8-16. If you want to really get "the right stuff", go to Advanced Nurtients on line and get something called Sensibloom A & B. I just made sure the M.G. had all the basic needs like nitrogen and phosphorus, zinc and magnezium. I also made sure it had something called, "molybdenum" in it since it seemed I needed that (according to charts and forums) for a little yellowing problem I had when they were young. It was amazing that almost over nite, with a little light blue nute water, my crop started to turn nice and dark green and flurish. Then as I said, I almost fucked up about a week ago "gett'n greedy" for more fluff and added a pretty bright blue batch of nute water thinking it will grow even faster and then "over nite" I saw major burning and death. I about freeked out. I immediately poured about 2 gallons of pure clean rain water (always catch rain water when you can) through the tubs and let it drain out the holes. Thank God, it worked. The burn stoped. I'm learn'n here too bud.