howmuch distance between HPS and plants?

Discussion in 'Growing Marijuana Indoors' started by closetbud, Nov 18, 2002.

  1. I'm gonna be growing in a wardrobe closet, approx. 2ft x 2.5ft x 5ft tall. The inside of the cabinet is white melamine, so the light will be reflected very well. My question here is how much distance to I need to keep between my HPS (400W) and my plants so they don't get burned? I read somewhere it should be at least 30 inches, which sounds like alot, but I've seen pics that look like there is less than 8 inches between the light and the plant. So how much space do I really need to keep between the light and the plants? The light is a hi-bay fixture where instead of a more flat shaped relector, the bulb is inside a metal dome with an open bottom. Looks like the lights you see in gymnasiums and such. I've got 2 options of mounting the fixture, I could either hang the fixture from the top of the cabinet (on the inside), but since it hangs down about 2 feet, this will only leave me about 3 feet of height for growing, and I won't be able to keep much space between the light and the plants. My second option is to cut a hole in the top of the cabinet and mount the fixture so that the entire dome is on top of the cabinet and the lamp is shining down into the cabinet, giving me a full five feet high of grow space. I'm going to be running 2 medium sized intake fans at the bottom of the cabinet and 2 exaughst fans at the top to help keep heat down. I would like to mount the entire light inside the cabinet to keep it looking stealth, but if I can't because of not enough space, I'll mount it on top. What do you think? Wow, sorry for the long post!

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