HLG 600's and leaf burn

IDK man... still looks like a K deficiency, which if your N toxic, it will lock out the absorption of K. And I think that makes it more light sensitive since it can't move water to the uppers if K deficient. Also can't convert carbs, so that may also make it light sensitive. But the fact that your problem goes away by moving them back into the tent is really weird.
Exactly, the problem goes away if I put em in my viperspectra tent. And I do compost teas, slf-100, photo plus microbes, and full like of nectar for the gods. My tent plants and outdoor love it. My hlg room even loved it when the lights were stupidly low, but as soon as I turned them up is when they burn.

Did you see the picture how they were doing it in early veg too? Well that didn't happen when they were in their veg tent, only after bringing em under the HLGs.

This happened during my last (and first) run in that room. It was a complete failure the plants burned to a crisp just like this. Everyone who I asked told me it was my soil and to flush them all with three times the amount of water in the pots, then calibrate my meter and start feeding them again slowly. Well I did that to half the room, and the other I just kept feeding like normal, and it made zero difference. They all burned just the same.
I really do not believe it has anything to do with the soil (although for a full two months I thought it was a nutrient issue 100%)

After a ton of trial and error and comparison I am nearly positive it has nothing to do with the soil.
 

oill

Well-Known Member
View attachment 5075570day 23 of flower. Exactly TWO days after turning my lights up to 800 ppfd.

I figured since they were done stretching and they're in full bloom they could handle it but they are pretty much dying. Obviously damaged leaves will never recover. I am around 300 ppfd now hoping they will heal and the green will come back. Just so wierd I never had these issues until I hung multiple quantum boards in an array. I used to run them at full strength 20" from the canopy in my 4x4 tents. I am stumped and frustrated lol
That's nothing to do with light... thats a nutrient issue. What's your nutes and room temps?
 
That's nothing to do with light... thats a nutrient issue. What's your nutes and room temps?
I follow the nectar for the gods full feeding schedule to a T. Doing feed, feed, compost tea. And my temps were like 77°f and like 68°f ish at night before I turned my lights all the way down, removed the pulleys and zip ties then directly to the ceiling
 
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madvillian420

Well-Known Member
That's not light stress. It appears to be heat-stress related. If it were light stress it would be fairly uniform across the top of the canopy. The pistils would be bleached and the top leaves would be fairly evenly yellowed/bronzed – they wouldn't be burned from the tips and edges inwards.

The most obvious clue is some of the lower fan leaves are showing the same symptoms.

A few questions to begin:

Why does your topsoil look so muddy? Are you using diotamaceous earth?

What is your CO2 ppm during lights out? What is it during lights-on? I understand this a completely sealed room?

Do you have an ozone generator or any other electical appliance that could be creating ozone in there?

That stress appears to be a form of heat stress possibly related to undertranspiration which I'm guessing is either to do with gas exchange or the fact that you have a sealed room that cannot evacuate enough heat. And/or possibly not enough oxygen during lights-out.

My bet is something to do with your CO2 management and lack of air exchange. When you turn up the lights, you are not only turning up light intensity – you are creating more heat. That heat has to go somewhere, otherwise leaf temps build up.

What is the difference in temperature when you have the lights dimmed to when you turn them up. Ie; what was the difference in temperature between those two days before and after turning up the lights?
this was my thinking. I dont know much about sealed rooms, so i wasnt going to say air exchange per-se, but lack of air movement being my suspected culprit.
 
this was my thinking. I dont know much about sealed rooms, so i wasnt going to say air exchange per-se, but lack of air movement being my suspected culprit.
I have four 16" oscillating fans on the walls , and only 4 led lights in the room. Is it possible I have too much air movement ?? Because there is a ton of air movement. I have four 10" fans on the floor as well to circulate air under the canopy
 

DoubleAtotheRON

Well-Known Member
I have four 16" oscillating fans on the walls , and only 4 led lights in the room. Is it possible I have too much air movement ?? Because there is a ton of air movement. I have four 10" fans on the floor as well to circulate air under the canopy
You'd notice wind burn before this would show up. Wind burn has a more reverse taco affect, and downward clawing. Kinda like this...
 

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You'd notice wind burn before this would show up. Wind burn has a more reverse taco affect, and downward clawing. Kinda like this...
Right, I'm familiar with windburn and have had it before, it's definitely not that. But my thought was maybe too much airflow could prevent the plants from breathing properly almost like a baby trying to breath facing the wind blowing ... Idk seems highly unlikely I'm just trying to think of everything
 

madvillian420

Well-Known Member
Right, I'm familiar with windburn and have had it before, it's definitely not that. But my thought was maybe too much airflow could prevent the plants from breathing properly almost like a baby trying to breath facing the wind blowing ... Idk seems highly unlikely I'm just trying to think of everything
nah, too much air flow wouldnt fry them like that even if you had too much.
 

DoubleAtotheRON

Well-Known Member
That a possibility for sure! You have this many spectrums going on in your tent......


Screen Shot 2022-02-05 at 6.29.29 PM.png

And then moving them into a single spectrum with a few reds in there. Im guessing your HLG's are 3000K... pretty common, and good from seed to harvest. However, it may be too much of a shock to them... just a thought.
 

madvillian420

Well-Known Member
That a possibility for sure! You have this many spectrums going on in your tent......

And then moving them into a single spectrum with a few reds in there. Im guessing your HLG's are 3000K... pretty common, and good from seed to harvest. However, it may be too much of a shock to them... just a thought.
i have a very similar veg/flower setup as OP, vipar blurples and Quantum boards for bloom and youre absolutely right, theres always a bit of a hiccup when you switch em from the blurples to the good stuff
 

madvillian420

Well-Known Member
Right, I'm familiar with windburn and have had it before, it's definitely not that. But my thought was maybe too much airflow could prevent the plants from breathing properly almost like a baby trying to breath facing the wind blowing ... Idk seems highly unlikely I'm just trying to think of everything
are the most fried tops by chance the furthest from your overhead oscillating fans? Theyre fried on top where light would be most intense and air movement most critical, just a thought.
 
My lights are spaced 4.5 x 4.5 from each other, although seeing now it does say 5'x5' canopy for flower. But those specs are for full power, mined were only at about 75% when they fried to a crisp
 
are the most fried tops by chance the furthest from your overhead oscillating fans? Theyre fried on top where light would be most intense and air movement most critical, just a thought.
The most fried tops (well leaves, the tops aren't burned or fried at all) are directly under the lights. In between the lights the burning isn't as bad, although it still occured. And there are no fans on that portion of the wall blowing between the light spaces (hope that makes sense)
 
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