Wattage of light needed?

[Nath]

400's are weak, 600's are the go. The give out the most lumens per watt. Never got into PAR ratings, but they always say lumens for humans, PAR for plants, so that would be something worth looking into also. Personally Ill only ever use 600's now, unless I start going with many lights, then 1000's are better since you can cut down the number of lights you use, just in case LEO come and bust me

[New Holland]

From what I've learn't 50 watts per square foot is ideal. 600 watters are the most effecient providing most lumens/PAR watts per watt, plus they give better penertration down to the lower buds on the plant. Therefore better yeild becuase the lower parts of the plant are getting more light.

 

More light does = more yeild. But like most rules there is always an exception. I read in OverGrow that if you exceed 7000 Lumens per square foot you will start to leech the chlorophyl out of the plants (make them turn white) which they need to turn light into energy they use. So I'd go with the 600. They cost about 7-8c/hr to run. So for a 18 light period each day it would cost about $1.30/day X 90 = about $110-$120 per quaterly power bill.

[Tom]

600 watters are the most effecient providing most lumens/PAR watts per watt, plus they give better penertration down to the lower buds on the plant. Therefore better yeild becuase the lower parts of the plant are getting more light.

Yeah, the 600w is my personal choice too.