Leaves are "folding" suddenly

[Papa OG]

I get it. I over analyze so much.

Sometimes, if I just take a step back. Try to just look at the basics. The plants will rebound with little to no issues.
I'm just trying to say from experience not all lights are equal, not all meters or readers are equal, and not all plants are equal.
Veg growth values from 300-600 μmol/m²/s during their vegetative phase.
And you're pushing your plants at 550 towards the top end of that Spectrum considering all things are perfect.

 

[Keffka]

I get it. I over analyze so much.

Sometimes, if I just take a step back. Try to just look at the basics. The plants will rebound with little to no issues.
I'm just trying to say from experience not all lights are equal, not all meters or readers are equal, and not all plants are equal.
Veg growth values from 300-600 μmol/m²/s during their vegetative phase.
And you're pushing your plants at 550 towards the top end of that Spectrum considering all things are perfect.

Agreed. Let’s look at the summary so far:

The issue is the original posted image showing what we believe is heat/light stress.* Classic tacoing of the leaves.

OP is saying these are clones he has the mother for, and this is an issue he has never seen before with those clones. The mother isn’t old enough to be producing unstable clones so these plants should be the same as they’ve been, technically.

OP also said everything is the same in the environment, and nothing exceeds a certain threshold. Both heat and light were mentioned as possibilities and he countered with measurements that shouldn’t have shown this type of issue

So, assuming all of this is true, there HAS to be some aspect of his grow that has changed. Whether it’s his light, or perhaps his measurement tools are failing. Something in the grow changed to produce what you and I know as heat stress. If these were seeds, different clones, or OP had changed something then I’d chalk it up to the changes made.

I’m avoiding light stress based on my experiences. In my experience plants that are light stressed don’t taco up and fall limp. They usually are super turgid with their serrations raised up, and their edges at a knife point. They’re photosynthesizing hard and fast but are trying to slow it down. This is assuming all other factors are good.

I have seen light stress cause the issues in OPs image however that was overwatering driving the light stress. The plant couldn’t photosynthesize efficiently to begin with and it’s having root zone issues, hence why it would look limp and stressed.

The weather has been changing fairly rapidly around here the past few weeks, it’s possible OPs environment spiked without them realizing it

 

[Keffka]

Here’s why I’m thinking more than light stress, these are my plants showing light stress

You can see the serrations are raised up making the leaves look sharp, you can also see them slightly tacoing. However they’re still turgid and standing tall. They are photosynthesizing efficiently, just really hard and fast. Too much light is their only issue. If this was driven by something else like heat or poor watering, I would see problems closer to OPs image

See what I’m saying with can’t relax? The shits a curse often

 

[Papa OG]

Totally agree.
It's definitely not the only issue.

I allow a little stress in my leaves, but try to refrain from praying hands, or Taco leaves. But it still happens from time to time.

 

[013]

I’m still the newbiest greenhorn in town so no claim to fame here. Totally agree there could be other contributing factors like seasonal changes in rh, even rather benign stuff you might never think of like adding or removing equipment.

Ever sit in grow room and listen? Of course you have. Ever notice how when the thermostat is satisfied on your oil filled heater a relay clicks off? Yes but then your fan picks up speed since there’s more juice available. Are you with me so far? So the fan runs at higher rpm when there’s more power and less load on the circuit. Same goes for your led, say 1 week ago you turn off that oil filled heater that’s been running since infinity / winter 2023. Now there’s more amps available to the led driver so it in turn runs hotter, throws more output. Heater loads and motor loads will cause spikes on your light circuit even if they are fed from seperate circuits. but it’s even more pronounced effect if it’s on the same circuit. It’s just how power demand works, the squeaky wheel gets the grease (heater loads and motor loads are the hogs) and everyone else must grin and bear it. Point is a simple change like unplugging a heater can make your lights burn brighter, maybe enough of a change that the clone freaks out

I think the main premise is still correct in that those fan leaves are folding up to reduce the amount of leaf surface exposed to photosynthesis… You know maybe Keffka is experiencing light stress while the OP (with whatever other contributing factors there may be) has nearly reached the point of light overload…

anywho, I yield to the experts, I’m always happy to be corrected and learn more

 

[Keffka]

Totally agree.
It's definitely not the only issue.

I allow a little stress in my leaves, but try to refrain from praying hands, or Taco leaves. But it still happens from time to time.

Yep, a little controlled stress is a good thing. Most of us do it in one way or another, whether we’re topping, droughting, etc.

I’m still the newbiest greenhorn in town so no claim to fame here. Totally agree there could be other contributing factors like seasonal changes in rh, even rather benign stuff you might never think of like adding or removing equipment.

Ever sit in grow room and listen? Of course you have. Ever notice how when the thermostat is satisfied on your oil filled heater a relay clicks off? Yes but then your fan picks up speed since there’s more juice available. Are you with me so far? So the fan runs at higher rpm when there’s more power and less load on the circuit. Same goes for your led, say 1 week ago you turn off that oil filled heater that’s been running since infinity / winter 2023. Now there’s more amps available to the led driver so it in turn runs hotter, throws more output. Heater loads and motor loads will cause spikes on your light circuit even if they are fed from seperate circuits. but it’s even more pronounced effect if it’s on the same circuit. It’s just how power demand works, the squeaky wheel gets the grease (heater loads and motor loads are the hogs) and everyone else must grin and bear it. Point is a simple change like unplugging a heater can make your lights burn brighter, maybe enough of a change that the clone freaks out

This is an excellent way to think and can definitely be a factor, especially in home grows. In a large commercial setting you may not notice these little shifts, but in a 4’x4’ area even your surge protectors can add heat to the room. Heck, they talk all the time about how LEDs don’t produce a lot of heat and oftentimes commercial operations need to supply additional heat. However in my 4’x4’ space my LED heats up the space by 10-15 degrees F every time it’s on. I’ve had to add cooling to the space to keep it under control.

Environments are so critical because there’s so many and so many variables. Great line of thinking @013

 

[Heinbloed]

so everythings back to normal again. The new leaves still look a bit foldet inwards, but after a few days they flatten. Think i made a big deal for nothing.

man if you start flower to early...that can have dramatic consequences for the yield. Last grow i was a little worried that i might end up with some plants almost reaching the tentroof again, so i switched when the plants were only about 24 inches tall...i used to wait another 7-10 days at that point, however, the decrease in yield was very noticeable.

i mean, thats not really the canoeing what ive got going on here do i?

 

[013]

Looks amazing, nice recovery!

 

[Delps8]

Good to see that things turned around.

The symptoms were those of light stress. Given that you reported that your PPFD was so low, I'd look into why your plants were reacting that way. The plants are, in terms of their ability to photosynthesize, at about their peak and should be able to thrive at 1000µmol±. If not, why not?

The point @Keffka raised is important re. watering. I've read grow journals where a grow could not sustain much over 500µmol and the cause was watering practices that hygrophobic soil.

How are you measuring light levels?

 

[Keffka]

Good to see that things turned around.

The symptoms were those of light stress. Given that you reported that your PPFD was so low, I'd look into why your plants were reacting that way. The plants are, in terms of their ability to photosynthesize, at about their peak and should be able to thrive at 1000µmol±. If not, why not?

The point @Keffka raised is important re. watering. I've read grow journals where a grow could not sustain much over 500µmol and the cause was watering practices that hygrophobic soil.

How are you measuring light levels?

I couldn’t get my room over 500 when my watering was off. DLI over 30 would fry my plants. I fixed my watering and now my plants are currently sitting 2 inches away from my light and are taking 1200 with ease. They won’t stay 2 inches away after I’m done training, but they’re also not being burnt. I have a commercial grade 4’x4’ fixture at 50% so it’s not like it’s a weak light either.

The worst part is, when your watering isn’t correct, you’ll see all kinds of symptoms that don’t seem to really fit well into any one category. You’ll wind up chasing your tail forever.

 

[Heinbloed]

now that were in flower i activated my additional Osram Oslon Square 660nmm now blasting 900 average with a very red-dish spectrum..nobody seems to complain but one little shipbuilder right in the cornor.

i hope that red wont make them strech even more...maybe i should wait 2 weeks..my gutfeeling tells me it wont make a big difference though.