How Many Lights?

How many HPS lights should i have to cover the area of three 3x3 trays.and what wattage should they be.

so should i have 2 400 watt lamps. will that do

will two 400w HPS do it ?

I would say you'd be better off with a 400w over each tray, and if the trays are adjacent, then the plants will get some overlap light.

HTH

potroast, a 1000W HPS uses very close to the same amount of power from the mains (~1100-1150W) as pair of 400s (~470-500W ea), due to ballast losses. A good batwing reflector with a diffuser allows even coverage of a pair of 3x3's with a single 1000. The luminous intensity of a 1000 makes much denser buds than a 400 due to significantly better foliar penetration.

thanks. without ya'll i wouldnt know shit