Hello everyone,

Again, I am asking for the forum's advice. I just set up my 430 HPS light system. It is on a six foot light mover and the grow area is 2 feet by 6.5 feet. The walls and floor are covered with white shower liners.

My question -- how high should the light be from the plants. After a search most people on this forum said between three to four feet. But is this from the table top or from the top of the plants. Or should I measure from the rim of the pot. This may seem like a hair splitting question but I am fearful of burning and killing my plants. HID is completely new to me.

Question two -- how long should I leave the lights on for? I keep my fluorescents on for 16 hours a day. I know this is to long for HPS.

I am just glad to finally get rid of the fluorescent tubes.

I can't wait to bloom multi's now.

Christian,
central NJ

Hi Christian,

Congrats on your new 430 W HPS system! :clap2: My light is about 2-3 ft above the tops of my plants depedning on the height size of my plants of course. Since your light is on a mover, I don't think you would have to worry about burning your plants particularly the multis. Also, my light is on a timer for 13 hours a day, every day. Hope this helps!

I agree with Pete, except my lights are on for roughly 16 hours a day. I haven't had many problems with burning, maybe I should turn them down a bit.