Just started growing i have a 150w hps much like one shown in pic, what is a good distance to keep light from plants
As long as you've got decent ventilation, and a fan blowing across the bulb, 4-6 inches seems to generally be about right from reading through the thread. The closer the better really, the best way to find out is to hold the back of your hand under the light for a minute - if you can take it without feeling uncomfortable, so can your plants.
The only exception is for very young plants or clones, or if you've just moved them from weaker lighting - in those cases you want it 8-10" away for a short while.
This is actually the reason I came on the thread.
My question is, how long do I have to leave the lights up high, after moving from 125W CFL?