Here's a good read:

http://boards.cannabis.com/indoor-gr...-progress.html

Quote Originally Posted by rhizome
Daily smoker? Husband/wife/roommate of a daily smoker? You'll want at least a 400w HPS for flower, and a 600 if you share a lot.

Multi-Smokestack household? A 600HPS will probabley keep up, but three Marley-types will want to go to 1 k. If you see yourself scaling up to small commercial, go for the 600- they scale up nicer, IMHO.
I'd say maybe 2 x 600w...(???) Compared to the 1000w, they are easier to cool, much lower electricity bills (from light and fans), and if you get everything else right, they will grow a lot of flame budz. :jointsmile:
bigtopsfinn Reviewed by bigtopsfinn on . how many lights will i need? hello im about 2 move out and sick of wondering if the next sack i get is going 2 be some flame or not and one thing that has held my interest more then anything is growing some flame budz all day i watch videos and read what i can but one think i cannot figure out is how many lights will i need... im a heavy smoker 5-8 blunts worth a day + i want some for close friends. i was thinking of a 10-15 plant system maby 20 if i need 2....with side room of motherplant and clones so i can keep it Rating: 5