I grow with a 400W digital ballast and grow about 6 plants under it in soil. I get an average of 3/4 of an ounce per plant. I'm new to growing but I do get better results with the seeds I bought online rather then from "bag" seeds. I have only been growing for a year now and I still want to add a C02 regulator and put 9 plants under the 400W HPS in a sort of SOG method. I once got 2 ounces off a plant that vegged for 30 days and flowered for 8 weeks. It was bubblegum from Nirvana and it actually turn a pinkish purple color. Another good yield strain is Top 44 and AK48 from Nirvana. The worst yield I ever got from a plant was a bag seed that yielded less than a half ounce. But it was good dense buds. All in all anything I have grown has been better than anything that I've bought on the street with few exceptions. Top 44 and Big bud from Nirvana are top yielders and are cheap to purchase. I can give you a link that sells Nirvana strains for $15 each and deliver to the United States a week after ordering. Good luck and I hope the info is useful.