thats alot of plants ,i dont know the nswer for sure but i would say around 8-10 400w hps lights,maybe am way off lol.
Personally I think it would depend on placement, preference and budget. I myself would go with no less than 600w Hps every 4x4 ft area. I'm a big 600 electronic balast fan though. They have the highest output to lumen ratio which saves money. Plus I can get em closer to the canopy. Just my 2 cents. Like I said preference.
I've heard of having 50 Watts/square foot thrown around before That would be 15000 watts! Geesh, seems a little high.
