I have a 1000 hps in a 4x5 foot room. technaflora recipe for success. average 1 pund a harvest. OOOOOOH, it's hydro.

I would go at least a 600 for that size room. or think ahead and get a 1000 digital ballast and bulb that you can dial-a-watt then if you ever move or expand your covered. or if you only need 400 you got it.