distance between 400W HPS and Plants

Hey guys, in my next grow i'll start using my 400W HPS but i have no cooltube.
can you give me any tips on how to make it work properly(distance from plants,ventilation etc)
thanks

I've been able to put mine around 6"- 8" with a fan blowing at the light. Without that, at least a foot.

thanks, i powered on the bulb just to try it since i have bought it about 1 month ago and didn't even know if it was working, i got surprised with the extreme it the lamp pulled out just with a minute on

XReaper said:

thanks, i powered on the bulb just to try it since i have bought it about 1 month ago and didn't even know if it was working, i got surprised with the extreme it the lamp pulled out just with a minute on

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yeah, if your ventilation isn't great... keep it about 10-16 inches away... a fan blowing up w/ a bowl of ice cubs or cold water behind in towards the light works well to keep things cool...

I'd suggest starting them under CFL's as opposed to starting them under the 400 watt from seed (if that's what you were going to do)... 2 weeks under the CFL's, then the rest of the VEG period under the HPS...

If it's too hot for your hand it's too hot for your plants. Usually about 6 inches is about as close as you want to get even with an aircooled hood.

A good rule of thumb is if it is not uncomfortable for you it will be ok for the plant

TheDifferenceX said:

I'd suggest starting them under CFL's as opposed to starting them under the 400 watt from seed (if that's what you were going to do)... 2 weeks under the CFL's, then the rest of the VEG period under the HPS...

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I agree...because of the intensity, the distance away you have top keep it starting out will make a seedling stretch.

sure , it makes sense, thanks a lot guys, i apreciate your help a lot

mine are 6in away with the fan blowing directly at the light. my plants love it

I have my plants about 2 inches away from a 600 wt HPS. All you need to do is to invest in a really good/powerfull inline fan. With a 500 CFM 6" canfan I'm cooling 2 600s and a 400 all HPS. temp in the growroom never goes above 78. temp 2 inches under the light is around 83 which is totally fine for my plants. The closer you get the better it is, you just have less coverage. 400s get pretty hot too(without a fan), I personally don't like the cool tube because of the hood(too small). as long as ur temp at top of the plant stays below 85-86 you are good.