400W HPS, How Far From Plants?

Im about 3 to 4 weeks from finishing my grow under cfls and ive just upgraded to a 400W HPS. How far should i have the light from my plants?

Around 1ft will be fine, I have gotten it to about 6 inches before.

Yeah as long as you have a decent fan blowing the hot air away from the tops or you'll burn them

well i have a 600W and they are like 6-8 inches away and they seem fine so yeah. with cooltube of course but thats close.

Does the HPS have tempered glass?

i've got my 400watt mh (4 wks into 12/12) 6-8 inches from my tops, no cool tube, or glass... i do have an ac unit in the room, with a fan blowing the cooled air up at the light, and when i place my hand at the same level as the tops of my plants, it doesn't feel uncomfortable. i'm sure your hps puts out more heat than my mh, but mine are loving the light they're getting!

if i was to mount a computer fan on one end of my shade and have it blowing onto the tube would this be effective enough to dispese the heat?

zechbro said:

if i was to mount a computer fan on one end of my shade and have it blowing onto the tube would this be effective enough to dispese the heat?

Click to expand...

ya that would help,but it would be good to have an oscilating fan blowing across the tops of the plants.