How much LED light can a plant handle?

Ryante55

Well-Known Member
I am testing out how much LED light a beautiful baby can handle. I have been stepping up light over the past 2 weeks since i switched to 12/12.

day 1 started with 400w cob
day 4 added 200watt LED panel
day 8 added 150 watt LED panel
Day 13 added 120 watt LED panel

so far shes thriving. Single plant in 3x3 coco drinking a gallon for breakfast and another gallon and a half for dinner.

how much can she handle? I plan on slapping in another 400w cob in a few days once she adjusts to the current level of light.

when does light burn set in?

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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
 

Lite

Well-Known Member
Is this the same plant that is in your grow journal? How long did you veg for?
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
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.
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
I am testing out how much LED light a beautiful baby can handle. I have been stepping up light over the past 2 weeks since i switched to 12/12.

day 1 started with 400w cob
day 4 added 200watt LED panel
day 8 added 150 watt LED panel
Day 13 added 120 watt LED panel

so far shes thriving. Single plant in 3x3 coco drinking a gallon for breakfast and another gallon and a half for dinner.

how much can she handle? I plan on slapping in another 400w cob in a few days once she adjusts to the current level of light.

when does light burn set in?

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Light burn sets in when the lights are to close to the canopy.
 

Lite

Well-Known Member
they were nt getting light burn but they were getting low humidity stress due to the actual radiation on the leaves. and @Humanrob I did start this as a clone, which makes up for ur missing 2 weeks :)
 

GreenLogician

Well-Known Member
i just said you couldn't burn your plants with led wattage.
I love leds, i'm about to convert my hps to strips and/or cobs.
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
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?
No clue. I just feed when I see it needs it, and cut back when I see burning
 

coreywebster

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?
With or without reflectors/lenses ?
 

CannaBruh

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?
You're frying them... try running each of those COBS at 10-20W
 

coreywebster

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?
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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CannaBruh

Well-Known Member
I've seen tons of bleaching from cobs, and it's almost always the temps are getting too hot for how close how hard we are running the COBS. Dial back the wattage or cool the room some and the bleaching should improve.
 

Michiganjesse

Well-Known Member
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