Leaf 'delamination' ? ... severe curling, in parts.

[Yozhik]

Yoz, again, we need an in-soil pH for sure,... this is not a leaf on the soil surface issue, or pests, or an infection, or very likely, a defc. issue either.... your excellent pics show the progression very well, but alas, I can't pin the problem down, at least not until we have a proper soil pH reading.... do you have a soil probe, like an Accurate 8? If you have to do a run-off test, use this guide ( https://www.autoflower.org/threads/...-testing-and-ph-estimation.41733/#post-928975 ) ...the run-off method is prone to measurement errors, but this one at least helps address those some,...it still looks most like the sudden pH shift symptoms I usually see in hydro, sometimes coco,... your EC, how much of that is the water, or are you using RO/DI? ...... I'm looking at the color of the dead tissue, and how fast it happens, how it dries out quickly, so much so that sometimes a little chlorophyll is still present,... I'm recommending a flush in any case, so do that improved r-o test first,.. make sure you have some RO/DI water for part of that test!

Hi @Waira - thanks again for your input!

I do not possess an in soil pH meter, so will grab one ASAP.
It's #1 on my to do list.

Regarding the water EC ... we have hard water here.
Tap water is pH 7.8-8.1 with EC of 0.5-0.6.
This is measured EVERY watering, prior to nutrients and pH down being added.

The only assurance I can give is that any pH shift has NOT been from any watering.
I am absolutely anal about the pH of the feeding I give the girls, and so far for this grow, is has been pH 6.3 EVERY time.
For there to be a pH fluctuation - which I accept there could have been given your far greater knowledge on the subject - it would HAVE to have been in the medium itself.

Can soil give this type of fluctuation?
That would kinda piss me off if it could, given how meticulous I am about the pH going IN to it!

Anyway - we'll know more once I get my hands on that in-soil pH meter.

 

[Waira]

oh yes my friend, there are many things happening in the soil, inputs, outputs, from us, the plant itself, and microbes!... that's my point, what you put in isn't the end of the story, and pH is not self managing in mediums, save a true well built and maintained TLO type soil,... get the Accurate 8, best for the $$,... there's a technique to using it, and it works on the same principles as those lousy skinny probe turds you see at garden centers, but it's more robustly built and plenty accurate.... again, that's my best guess at this point, a pH snafu,...

...off to smoke out and relax for the eve,... catch you later Yoz!

 

[Yozhik]

@Waira ... is this the Accurate 8 probe, by CWP Instruments, you speak of?

 

[villain1]

Suggestion elsewhere is that it may have been caused by the leaves resting on freshly watered soil ... which does make sense.
I do remember that this plant, did have some low lying leaves, and there is a very distinct possibility that they have have been low enough to rest on the soil, if not slightly immersed.

I can't specifically remember it happening, but cannot write it off.
It 'feels' like a very probable answer.

Would this be consistent with your analysis?

@Yozhik

Maybe these pics will help eliminate at least one thought you have of the problem
Was watering today and thought about this post so took a couple of pics
The plant is 4 weeks old and for the last 2 weeks the leaf has been resting on the soil

 

[Roark]

Here's my thoughts. I am NOT. Soil grower.
I recently finished a grow and have the stock an still sittling in the coco in the table. I have not been watering it, cause I chopped it all down. The fan leaves that remained look similar to this. And seem to follow a similar progression. I look at it as there are nutes with nowhere to go. In your case its like nute build up in the fan leaves. Plant is till small and over fed. Like a goose. All fat an happy but she maybe sick from all the food.
My cbd skunk haze started dumping a ton of fan leaves in flower I upped the ppm and it didn't help. Once on the super model diet she perked up a bit. Meaning I went from 1300 ppm to 249ppm.
Flush and lighter ppm's could be helpful.
Also, with the nugs from the cbd sunk haze drying on paper towels I noticed something very interesting, I have what appears to be nutrient solution spill spots. I do a half water cure and rinse on all my plants. The water comin off the buds looks all pinkish like solution not green from the chlorophyll. its strange cause I flushed the hell out of her for 2 weeks.
Short story long....could be over fed with nowhere to go.

 

[Yozhik]

Hmmm ... ok ... so then would THIS be symptomatic of the same problem?
Or a SECOND issue I now have to deal with?

 

[Roark]

Looks like nute burn to me. Or to say that is how I would treat it. Sorry, what's your ppm or e.c?

 

[Roark]

Okay just looked again at e.c 1.9 so like 950 ppm. Not high going in. However, if its NOT flushing through the bottom then its building up. Issue I have found in pot/container growing. Could flush til they, in solution and out solution, match up. Ph of cousre. then feed like you normally do. Again, this is how I would treat the situation. And that's in coco. Cause I'm no worm.
Hope that helps.

 

[Yozhik]

Okay just looked again at e.c 1.9 so like 950 ppm. Not high going in. However, if its NOT flushing through the bottom then its building up. Issue I have found in pot/container growing. Could flush til they, in solution and out solution, match up. Ph of cousre. then feed like you normally do. Again, this is how I would treat the situation. And that's in coco. Cause I'm no worm.
Hope that helps.

Yeah, the EC of the tap water is ~0.6 ... EC post-nutes is ~2.0.

Watering always gives runoff - not excessive - but some.

 

[Roark]

I think of it like this, again in coco, nutes build they build slowly even with decent run off. So some inevitably stack up like layers, then as the roots grow down chasing the food an water or whatever roots do the will run into say a sharp increase of something. Blamm problems! Only way I can think to solve is flush heavy to wash away the layers. Start over basically. Hence the term less is more.
Its the foundation I work with in my grows, in containers, and it has served me well.
I accept that I could be wrong and some one with more experiance may state that.
However it is not an issue I have had in my flood tables, filled with coco and they drain very well.. So that's my pudding. You'll have to becareful in soil not to drowned yiur roots.