Lights distance from plant?

Swisher Sweet

Swisher Sweet

Active Member
I have received varying info on this subject. I have had my plants no more than 20 inches from the plant and no closer than 14. I was told this was too close although the plants are very healthy. I use two 400watt HPS with a fluorescent in the middle. What's the thought on this?
 
sweetsmoker

sweetsmoker

Well-Known Member
id say 14" is optimum, theres alot of intensity from that set up, even if the heat can be managed, the intensity will cause foliage probs, it wont kill her but isnt ideal,, how many u gt under there?
 
Swisher Sweet

Swisher Sweet

Active Member
10 Sativa and 5 Indica 10 days into flowering. Tight squeeze but plants are really healthy and buds are forming. I don't appear to have a heat problem (70-80 degrees during the day an 70 at night). Growing in a 5x5x8 bathroom with ceiling exhaust fan an oscillating fan on floor blowing in.
 
bigbudmike

bigbudmike

Active Member
sweetsmoker said:
id say 14" is optimum, theres alot of intensity from that set up, even if the heat can be managed, the intensity will cause foliage probs, it wont kill her but isnt ideal,, how many u gt under there?
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Really its all about temps. If you can keep your temps under control then you could put the lights as close as you want. I have seen plants just inches away from a 1000w HPS with no problem as long as you dont burn the leaves. A cool tube helps if you dont have one. Even better than that is the liquid cooling system that is on the market. The plants love as much light as possible but not heat. Hope this helps. :bigjoint:
 
bigbudmike

bigbudmike

Active Member
Swisher Sweet said:
Does it sound like my setup is OK?
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Sounds great. 2x400w Hps very good at 14" you shouldnt have any problems. I use smaller cooler lights because I only raise and harvest 1 plant at a time. I can keep my 2x150w Hps just inches from the tops of the plant with proper ventilation.
 
2beanklm

2beanklm

Active Member
i have 2 600 hps and had them about 10" away at one point , but i crisped the top leaves abit really with the 600s i thnk 18" is close enough. i would think for the 400s 12"-18" would be fine. if you are real close keep an eye on them as mine appeared fine then all of a sudden they didn't seem to like the heat any more. seemed to happen when the pots were on the dry side right before i watered them. it is my first grow though so please use this as a suggestion not an educated opinion..
 
Swisher Sweet

Swisher Sweet

Active Member
2beanklm said:
i have 2 600 hps and had them about 10" away at one point , but i crisped the top leaves abit really with the 600s i thnk 18" is close enough. i would think for the 400s 12"-18" would be fine. if you are real close keep an eye on them as mine appeared fine then all of a sudden they didn't seem to like the heat any more. seemed to happen when the pots were on the dry side right before i watered them. it is my first grow though so please use this as a suggestion not an educated opinion..
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I fyou look a t that chart in this thread Rich Ed sent me it will be helpful.
 
secretforestgarden

secretforestgarden

Active Member
Any info on 35w HPS? I use it w/ conjunction of a 50w LED panel, a 13w LED panel, and a 42w CFL in a PC grow case. I know hardly anyone uses a 35w HPS (I have heard of a few) but any info on distance w/ a half-decent mylar reflector system would be killer!
 
Relaxed

Relaxed

Well-Known Member
12 inchs for 400 water down to about 24 inchs. Booster seat the plants to level at 12 inch tops. Let em go to about 9 inchs for mature plants as they can take the heat stress better. What ive read and works like a charm. Noticing as with all plants too close is not good for em (yield and yellowing faded leaf issues). When they are treated well they sway in the wind nicely with thru the grow green all over....not dieing.
 
Relaxed

Relaxed

Well-Known Member
oh,

- get a 12 inch ruler for quick measure from light to plant top for the room.
- get a string measured to 12 inches and hang a bolt or something for weight. Hang it from your chain hanging next to the light for immediate height monitor daily of growth spurts and when you need to raise the hood.

tip for the day....
 
Relaxed

Relaxed

Well-Known Member
Mh should be no different.....the watts are the same so heat will be...if this were April fools day id swear you....never mind
 
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