# plants how far from this hps light?



## gunnjabsgrow (Jun 27, 2007)

i got a 400w hps light here with the ballast in the light fixture. all inclosed just a box with glass on the bottom for light to travel out. i have a 12" fan that i am goin to point directly on it and turn high speed to keep it cool. i have a few plants flowering and am wondering a general distance i should keep them without burning them or stretching them to much.    thanks


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## maineharvest (Jun 27, 2007)

I keep my 400 hps about 18 inches from the tops of my plants.  I also have a thermometer in the closet so If it gets too hot I raise it up a little bit.   I keep the temp around 75-80.   Today it is about 100 degrees outside and my apartment is like an oven.  My growroom is 88 degrees and there is nothing I can do.  Im very nervous right now.


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## LaserKittensGoPewPew (Jun 27, 2007)

^^^ Your plants can easily withstand 88 degrees. Keep in mind cannabis is a weed that has evolved over thousands of years outside in the wilderness. If you keep your plants root zone cool you won't have any problems. You can do that by covering the soil in the pots with moist paper towels.


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## berserker (Jun 28, 2007)

gunnjabsgrow said:
			
		

> i got a 400w hps light here with the ballast in the light fixture. all inclosed just a box with glass on the bottom for light to travel out. i have a 12" fan that i am goin to point directly on it and turn high speed to keep it cool. i have a few plants flowering and am wondering a general distance i should keep them without burning them or stretching them to much. thanks


Here is a perfect chart that you can use to help you.Hope that it works for you,and keep it GREEN:hubba:


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## gunnjabsgrow (Jun 28, 2007)

thanks everyone. i just started 12/12 and the tops are around 14 inches away. we are checking them every few hours just to see what the heat is like. thanks


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## Dankerz (Jun 28, 2007)

you shur thats a 400watter? it looks like a 150watt?


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## pastor420 (Jun 29, 2007)

I have a 250W that looks very much like that.  Same bulb type too.


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## gunnjabsgrow (Jul 2, 2007)

its a 400w i am 100% positive. the bulb says right on it 400w.


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## SmokinMom (Jul 2, 2007)

Awesome chart berserker!


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## pastor420 (Jul 2, 2007)

There is always the old rule of thumb as well.  If it's too hot for the back of your hand, then it's too hot for your plants.


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## passafire420 (Jan 15, 2010)

what about seedling under 600 watt hps


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## Todway (Jan 25, 2010)

many guides suggest 1-ft. of distance per 100w of output. Just yesterday the clone-master at Blue Sky in Oaksterdam reiterated what many always say: no closer than THREE FEET to the plants with HPS or MH 250W and up bulbs.


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## Todway (Jan 25, 2010)

for seedlings etc,. you only need either:  75w and or 120w Philips grow bulb(s), or  -  better -  the 75w (17w consumption) 24-in. fluourescent plant tubes at Wal-Mart (about $10 each). Well made, and durable.   After that, two 48-in. fluor Eco-Lux or Philips Plant/Aquarium tubes, about $9 each or so, and the fixture is $10 each at Home Depot.  After that, 125w MH and reflector or skip to 250w MH.  Then, either 400w HPS or skip to 600w HPS.  One vendor I use sells switchable HPS / MH electronic ballasts with long cords and a 3 yr warranty, for $125 or so each, from VA.


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## BBFan (Jan 25, 2010)

Todway said:
			
		

> many guides suggest 1-ft. of distance per 100w of output. Just yesterday the clone-master at Blue Sky in Oaksterdam reiterated what many always say: no closer than THREE FEET to the plants with HPS or MH 250W and up bulbs.


 
Hi Todway!

I have to ask......  Why no closer than 3 feet?

That statement runs contrary to everything I've read, seen, or experienced.  Perhaps for new clones, but for a grow?


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