Distance to put a 600 watt hps from top of plants

I am growing 4 lowryder AK-47 seedlings under a 600 watt hps lamp, and I am wondering how far I should put the light away from the tops of the plants.

18- 24 inches away my 600 is 18 inches away and i have a fan that blows air inbetween that space

Is it an air-cooled hood? With the air flowing through my hood, I can keep my light about a foot away, less than that with an additional fan blowing over the tops.

I have a fan hooked up to the light that blows air through on the bulb, but I guess that I will put another fan below that blows underneath and in between the fans, I just feel like 18-24 inches is too close for seedlings, but I guess not. I had raised my light higher than this because i noticed that the leaves seemed to be very light green and I thought it was a result of the light being too close.

24 to 36 inches is ok for seedlings they will let ya know if they don't like it

You may want to get a very mild organic fertilizer such as maxicrop seaweed extract to help the pale green color of those seedlings. They will need the nitrogen!

pnk7948 said:

I am growing 4 lowryder AK-47 seedlings under a 600 watt hps lamp, and I am wondering how far I should put the light away from the tops of the plants.

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i got 2 with ajust a wings and super spreaders...... with the super spreader i get my hps 4-5 inches from the girls

4 to 5 inches from seedlings..lmao

wiseguy316 said:

4 to 5 inches from seedlings..lmao

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not seedlings clones... dont be rude... jus ask
and FYI with the super spreader it would work WITHOUT burning'em

I apologize, I overlooked that you were starting seedlings under the HPS. I normally start my seedlings and clones under cfl's and then switch to HPS when they switch to flowering. I would keep it a couple feet away at first for a few hours and then move it closer once you know your not burning them.