i'd say no more than 3... and i would make your room a bit smaller. you want a good 50w or more per sqft to get a good crop

maybe you could make your room 1'x3' and grow 3 plants taking up 1sqft so they get adaquite(sp?) light, but that also depends on what you're planning on growing. sativa or indica?
UMrocksmysocks Reviewed by UMrocksmysocks on . 175W MH- how many plants? I have a 175W MH/HPS ballast. How many plants can this light successfully grow? I have a 4x4 area to work in.. Thanx! Rating: 5