hight of light

I'm curious I was reading to do to many growers keep their lights to close to the plants...

What is a suggested hight, I personally dont want to constantly raise and lower my light due to it being aircooled

what watt are you running?

How close you can get depends on the amount of air your moving through the reflector and wattage of bulb. I have 1000w air cooled and can get 15 inches or so above the canopy without problems, but I prefer to leave 18 inches. The only reason I got that close was because I vegged to long and ran out of head room. Ive always just held my hand/wrist, palm up, under the light and if I can hold it there for a good 20 seconds without discomfort then it should be ok.

I'm running 400 watts but I wanna know if I keep it about 5" above the plants should I be fine?

Why do you have to "constantly" adjust the lights because they are air cooled? I don't get it.

Exactly what Bomb Hills and brimck325 said-- depends on what lights you are running (HPS? CFL? T5? MH?)and the wattage AND how you are cooling them...

with T5 and CFL-- you keep them just a couple inches away- enough to not burn... with HPS/MH you keep them high enough that when you place your hand palm-down at plant height you barely feel the warmth... meaning if they are air-cooled in glassed-in hoods, they can be much closer than non-cooled or open hoods.

No matter what lights you use- you 'constantly' adjust as the plants grow so they are not too close and burn- or so far away that they stretch and F***-up the internodal spacing...

AimAim said:

Why do you have to "constantly" adjust the lights because they are air cooled? I don't get it.

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lower and raise them as the plants begin grow I'd raise them or can I just set them to a fixed height and be done?

RedzoneFL said:

lower and raise them as the plants begin grow I'd raise them or can I just set them to a fixed height and be done?

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you can do it either way but just remember the closer you get it the more penetration you will get and with a 400 your gonna want as much as you can get

RedzoneFL said:

lower and raise them as the plants begin grow I'd raise them or can I just set them to a fixed height and be done?

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No, you need to keep the distance between your lights and plants optimized, which normally means raising the lights as they grow. If you set up your lights right this can be 10 seconds work every other day.

the light and air cooled fan for my carbon filter+ is operated by the same---I will have to buy another fan... :/

for a 400 watt 12"+

i keep my 150 watt like 12" from the canopy, and i may raise it becuase of heat issues.