LED light saturation nation

my last grow i could not get the light dimmer above 40% without causing all four strains (except for the more sativa looking one) to lose chlorophyll (except near the veins) and slow way down. at that time it was in winter with almost no humidity and that seemed to be a factor

this time it was late summer/fall and this new strain has done the same thing all the way down to the lowest dimmer setting or just slightly above

i keep the lights over two feet from the plants btw and well ventilated

More info nèded
What make is the light?
What size is that area?
How many watts is it running at now?
What are you feeding them?
They look under fed

dank'd said:

my last grow i could not get the light dimmer above 40% without causing all four strains (except for the more sativa looking one) to lose chlorophyll (except near the veins) and slow way down. at that time it was in winter with almost no humidity and that seemed to be a factor

this time it was late summer/fall and this new strain has done the same thing all the way down to the lowest dimmer setting or just slightly above

i keep the lights over two feet from the plants btw and well ventilated
View attachment 5330877
View attachment 5330878

Click to expand...

Its not the light causing problems What you growing in? What are you feeding? Do those bags have drain holes What about the tote?

Moflow said:

More info nèded
What make is the light?
What size is that area?
How many watts is it running at now?
What are you feeding them?
They look under fed

Click to expand...

kingbrite 240w, see pics for area, dimmer all the way down, pro-mix moisture mix omri certified with 3 months fertilizer included + water

they look light saturated actually, which is as you said shown by the resulting nutrient uptake deficiency, that's how plants look apart from the infamous bud too near the light spot bleaching

this is the second wave after trying to bump the light up just a smidge again, the first wave is why they lost (i had to remove) the fan leaves. light saturation shows as general chlorophyll loss but still green at the veins and the plant slows right down

after doing some research online, this is apparently a thing with led's. many accounts of people moving plants from hid's to led's and they crap out just like with me (from florescent) two years in a row with all different strains

i can still grow healthy and quality plants though, so really this is a win for energy conservation and longevity of the light. i only posted this time because this strain has me turning the light dimmer all the way down that's all. i will maybe disconnect an led bar also. win win

thumper60 said:

Its not the light causing problems What you growing in? What are you feeding? Do those bags have drain holes What about the tote?

Click to expand...

i gave the bags drain holes but there would never be enough water to make it down that far. i realize i can get a few crops out of these now which is good for 13 cdn per bag. promix moisture mix is omri certified with 3 months fertilizer and is good soil i have used it before

although this strain is slow growing and the seeds might be getting old, this is the same situation as my previous grow with four strains from another breeder

if it happens it's too late. however, turning the light down will rejuvenate the plant in 2 or more weeks but... any attempt to bump the light back up is risking going through that process again, and the effected leaves for the most part do not get chlorophyll back especially the fan leaves

and i remember growing seed from thai weed in the basement of a townhouse in 94 with a 1000w mh on the ceiling studs and the plants on the concrete and at just a few inches the thais had dinner plate sized healthy green fan leaves(!)

The problem was not too much light.
If you had the light at 24" it was roughly 550 ppfd max at 100% power
Unless they were delicate seedlings, that amount of light will not cause issues.
Your problem lies elsewhere

Billy the Mountain said:

The problem was not too much light.
If you had the light at 24" it was roughly 550 ppfd max at 100% power
Unless they were delicate seedlings, that amount of light will not cause issues.
Your problem lies elsewhere



View attachment 5331275

Click to expand...

oh it most certainly is the light, and it's not just me this is not uncommon

all good though i found the sweet spot where the plants will be fine and for this strain it is with dimmer all the way down. last time it was dimmer at 40%

just bump it up above these levels and boom like clockwork the plants crap out

good thing is it is saving energy and light use : )

dank'd said:

oh it most certainly is the light, and it's not just me this is not uncommon

all good though i found the sweet spot where the plants will be fine and for this strain it is with dimmer all the way down. last time it was dimmer at 40%

just bump it up above these levels and boom like clockwork the plants crap out

good thing is it is saving energy and light use : )

Click to expand...

That 240w light at 40% and 2 feet is around 250 ppfd, that's simply not enough intensity to cause light bleaching.
Your second experience with the light set at minimum and still having the same thing happen is only further confirmation that the light intensity was not excessive.

dank'd said:

oh it most certainly is the light, and it's not just me this is not uncommon

all good though i found the sweet spot where the plants will be fine and for this strain it is with dimmer all the way down. last time it was dimmer at 40%

just bump it up above these levels and boom like clockwork the plants crap out

good thing is it is saving energy and light use : )

Click to expand...

Weak plants cant take much light. You need to fix the other parameters in your grow and then increase the light.
There's a linear correlation between amount of light and yield. So if you "save" electricity you just get less yield.

dank'd said:

i gave the bags drain holes but there would never be enough water to make it down that far. i realize i can get a few crops out of these now which is good for 13 cdn per bag. promix moisture mix is omri certified with 3 months fertilizer and is good soil i have used it before

Click to expand...

There is no way this is just from your light being “too strong”. I used to keep plants 14 inches under a 1k hps and only got light stress or bleaching on a couple plants in-over 10 years. You insisting it’s the light will not help you figure out the real problem.

Personally I would say it’s an issue with your watering habits and feed. If your bags have drain holes but you never give them “enough water to make it down that far” then your root system is being starved and limited at the bottom. Plants need enough water to grow.

secondly is the feed issue. You might claim it’s great soil because you’ve used it before but you have also had issues before. I’ve never seen people have good results trying to use time release nutrient precharged medium. You have no idea how much or what nutrients are in your medium and that will quickly result in deficiency issues. Especially as plants get older and larger they need more nutrients(to a certain point).

Turning your lights down may have helped your plants recover because it slowed the metabolism down to a point the plant could survive off the nutrients it had but that will greatly limit your final harvest.

What Temperature does your grow space stay at? Temperature is another major factor in plant metabolism, if it’s too cool they can’t uptake and process nutrients properly.

The goal should be to increase the quality of your environment. Improve the humidity and temp control so the plants biological functions can happen smoothly and it’s not struggling or stressed. Then provide appropriate light for the space and feed the plants accordingly to keep them healthy. This will result in the best yields and quality possible based on the genetics you are using.

ya me too that's why this thread is about led's not flouros or hids

here is a quote from the following thread which explains the situation:

"The highest recommend distance on the website was killing my plants. 3 different strains all very healthy until placed under this led light and returned to healthy after removing. It didnt stop until it was almost 3 feet away and Im sure the PAR value is dismal at that distance due to the reverse square law. The same sister plants next to them under a close open bulb 400w MH is already 6 inches higher in growth."

https://www.420magazine.com/community/threads/my-leds-are-killing-my-plants.239747/

dank'd said:

ya me too that's why this thread is about led's not flouros or hids

here is a quote from the following thread which explains the situation:

"The highest recommend distance on the website was killing my plants. 3 different strains all very healthy until placed under this led light and returned to healthy after removing. It didnt stop until it was almost 3 feet away and Im sure the PAR value is dismal at that distance due to the reverse square law. The same sister plants next to them under a close open bulb 400w MH is already 6 inches higher in growth."

https://www.420magazine.com/community/threads/my-leds-are-killing-my-plants.239747/

Click to expand...

That is called anecdotal evidence, which means it doesn’t prove anything because it’s not based in fact.

If you are dead set that it’s the light that is causing the problem, then replace the light and be done with it all. Why even ask people for help if you already know the answer?

Or you can listen to the various people that tried to analyze your situation and offer some suggestions that might actually solve your problem.

I just went through this same issue. Moved a plant from veg tent to flower tent, it would start yellowing within a day or two. I thought it was the light. Switched to my previous light, I had the same problem. Turns out I needed to up the nitrogen. Higher ppfd = higher nutrient consumption.

thanks for the replies everyone this is really an interesting conundrum. on another forum having the same discussion

what i think i know now is the rh really needs to be bumped up with led's which i will not be able to do in this closet grow heading into winter. also gypsum/calmag apparently has a major protective(?) rejuvenating effect for plants that have these problems under led's

so for me it looks like either grow with leds on low/lowest dimmer settings at 2 1/2 feet from the plants, or get an hid. so far i have not had any good weed from the led it was all decent looking and healthy but tasteless and mostly odourless. whatever taste or smell there was was harsh and/or weird

dank'd said:

thanks for the replies everyone this is really an interesting conundrum. on another forum having the same discussion

what i think i know now is the rh really needs to be bumped up with led's which i will not be able to do in this closet grow heading into winter. also gypsum/calmag apparently has a major protective(?) rejuvenating effect for plants that have these problems under led's

so for me it looks like either grow with leds on low/lowest dimmer settings at 2 1/2 feet from the plants, or get an hid. so far i have not had any good weed from the led it was all decent looking and healthy but tasteless and mostly odourless. whatever taste or smell there was was harsh and/or weird

Click to expand...

What nutes are you using? What ratio, what level?

Hollatchaboy said:

What nutes are you using? What ratio, what level?

Click to expand...

promix moisture mix omri certified it has 3 months fertilizer in it. i have used it before in flouro, hid and sun and it is good soil

Bro. Better light means your plant wants to and can do more. Your mistakes are
1. Your knowledge.
2. Your ego.
3. Asking another forum
4. Watering techniques
5. Probably lots more

With LED, temperature and humidity play a much bigger role than with HID. You need Temps in low to mid 80's, and an appropriate humidity to have a proper VPD. Once that is in the correct parameters you can focus on nutes and light intensity, but not before.