How much LED light can a plant handle?
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Humanrob
Well-Known Member
I run 750w of qb at 700ma over a 4x4 plants are about 16 inches away with no problems I'll put the light a couple feet away when I first plant the clones but that's more to add a little stretch so I can lollipop. I'm guessing you need over 50w/sqft to cause any issues
CannaBruh
Well-Known Member
the point to take home is i get much much better results at 20W/sqft than i was getting with 60W/sqfti don't care about my g/w, im going for total G. I am on equal payment for my power company and am moving at the end of this rate year.
Lite
Well-Known Member
7 weeks, yes it is. i reduced down to 855watts due to canoeing and one lights fans breaking. I guess the answer is, in a 3x3 tent, dont exceed > 1000 true watts of LED. The fans couldnt stop the extremely low humidity caused by that much light.
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Humanrob
Well-Known Member
Based on the massive trunk on that thing I would have guessed 9 weeks, but some plants grow faster than others. With light there is a point of diminishing returns, and then there is a point where it becomes detrimental. You have mentioned two goals (I'm paraphrasing but hopefully not misunderstanding): (a) to see how much light the plant can take, and (b) to try and get 1+ lbs from the grow. The answer to A might undermine the answer to B. In other words, how much light you can give it without killing it might give you a stressed plant that yields much less than a plant with an optimal amount of light. I don't know much about red/blue LEDs, and I don't recall reading how much light will give you the healthiest happiest plant possible, but it looks like you'll find out. With COBs, there seem to be a lot more people on RIU are testing and sharing their information, and depending on your feeding style between 37.5w and 50w per square foot is a safe and happy range.
Keep that plant happy and I'm sure you'll pull a pound no problem.
mr sunshine
Well-Known Member
Light burn sets in when the lights are to close to the canopy.
Shawndeadhead
Well-Known Member
Yep yep yep 500W DIY led cobs over 4x4 2lb
1000w hps over same 4x4 same strains 1.25 to maybe 1.5 lb best.
GreenLogician
Well-Known Member
I seem to burn my plants with cobs real easy. But maybe I'm just not keeping up with the nutes?
I've got six cxb3950s in a 80x80cm, and I get my leaves yellowing off if I run them much above 250w.
It's been recommended to me that I need to keep my temps right up?
Lite
Well-Known Member
No clue. I just feed when I see it needs it, and cut back when I see burning
coreywebster
Well-Known Member
With or without reflectors/lenses ?
CannaBruh
Well-Known Member
You're frying them... try running each of those COBS at 10-20W
GreenLogician
Well-Known Member
120 degree lenses.
That's what it feels like! Why is it like that for COBS, when people like the OP can go cray cray with the blurples?
Maybe plants are more easily stressed by high levels of green, or something not in the blurps?
Yodaweed
Well-Known Member
I'd suggest using a 315 cmh, you could get some really good light coverage from a single cmh in that sized area and the quality of spectrum is much better than those LEDs.
coreywebster
Well-Known Member
Blurples don't put out the photons cobs do. But ive seen really bleached buds from blurple. My cobs don't bleach anything 6" from main colas. But I run with no reflectors or lens. I have not seen a proper cob bleach a bud site on anyones grows yet.
My QBs can give light burn to fans if I'm not careful, not surprising though, they give solid buds 3 feet down. My cobs don't penetrate that far, but like I say lack of lens means more light spread out, not so many hotspots.
I think I would just raise my light if possible rather than dim, get them beams blending better.
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Michiganjesse
Well-Known Member
Lovee
My 315