Will this HPS 400w bulb ( Amazon.com: LU400/MOG 400-Watt ET18 High Pressure Sodium Bulb, E39 Mogul Base, Clear: Everything Else ) work for veggie, how many square feet will it cover. Will this MH 400w bulb ( SYLVANIA 64490 - 400 Watt - BT37 - METALARC - Metal Halide - Unprotected Arc Tube - 4000K - ANSI M59/S - Universal Burn - M400/U | 1000Bulbs.com ) work for flowering, how many square feet will it cover.
Metal halide is for veg and GPS is for flowering But you can't just plug those bulbs into a regular socket. You need a special socket which is in all growing reflective hoods and you also need a ballast
That would be quite weak for a 4 x 4 area. I would not do any more than 8 square feet with a 400 watt light. Rule of thumb is 50 watts per square inch up to 80 watts per square inch.
^square foot i think you meant also, yeah, i had a 400w in my 2x4...it was okay...bumped it up to a 600w lumatek with an overdrive setting....muuuuuuuuuuuuuuch better for the same space....just gotta be able to manage temps at the plant tops.
lol, yeah, I didn't notice that. I did mean square foot, not inch. 50 to 80 watts per square inch should sound good.