If you think a 400 watter can cover 4x4 you must be keepin that light LOW as hell. mine gets close to 4x4 but it doesn't pump the plants enough, bigger is better. whatever you get, go with a grolux bulb by sylvy.
Peace.
Specialist Reviewed by Specialist on . Unsure about 400 VS 600 HPS I plan on having a 16 plant sea of green in a 4X4 (one plant per square foot), using some kind of hydro (flood and drain) in some kind of medium. Now my question is, even though all the books say 400 watt HPS is OK for a 4X4, will it be enough for 16 plants? Would it be OK to suppliment it with some CFLS or do you think it's neccessary I get a 600w? Rating: 5