My space is only 4' X 2', and I get 1.5 to 2 lbs per harvest! My peak lumen output on my canopy is approx 131,000 lumens, whch is waaay over what is "normally" recommended. But, I started way lower, obviously, and I found that the more lights I added, and the better I controlled my temps and air flow, and the more systems I integrated, like the CO2 system, the grate and drain-pan with sub. pump and float switch, and proper electrical equipment like enclosed time clocks, and ltg contactors, instead of those cheap-ass little push-in/pull-out kind u find at the dollar store, and all that, I started going from like a cutie pie, on up to a pound and even got 2 on my last one with only 6 massive plants! So, with eleven going at week 4 of flowering now, seven in five gallon buckets, and four in med size pots, I am expecting a bumper crop... It's like a fine-tuned machine now, with the fans just right and everything working in perfect harmony... U can do soooo much, with what seems like so little...