i have a small box grow room i have 5 seedlings and 1 400wtt hps light how high should i be hanging this badboy over my babies please help..........
A brand new 400w HPS bulb should be at least 11" from all plant parts at all times. Setting it to 13" each day provides room for growth. That's from the bulb, not the lamp.
Hold your hand under the light, if its too hot then move it up. Smaller plants like the light to be right above them or else they stretch trying to reach it but don't have it so close that you burn them. I use CFL's for veg just so I can get them real close, I switch over to HPS when its flower time. When I did veg using my 600w HPS I found it had to be about one and a half feet - two feet above them.
yeah i was worried about them going mental so i had it like 5 maybe 6 foot above but with some reading and help from u guys i think i need to move it to about 2 foot about the little beggers thanks.