Help!! Genuinely CONFUSED, what is going on?!

Hello there folks!

I'm about a month into this grow, 30 plants of Dutch Passions MasterKush, in 11l pots.
I'm using two DIY-LED-Fixtures, made out of Bridgelux EB-strips Gen2 3500k, paired with HLG-480-42AB. Strips are driven at 700ma!

Plants are growing, and seem to be overall healthy, except for one small aspect: these little spots that you can see on the pictures. As i said, they seem to be healthy in every other regard, so im very confused. Older leaves seems more affected then the newer ones, as you can see. This has been going on for a couple weeks or so, and i just can't seem to pinpoint what the cause is..

I feed them Biobizz fish mix, along with some Canna Calcium as well as Canna Mag..
Temperatures are at 24c, with about 65%RH. I keep feeding at a minimal: i use nutrients at half strength and i add 1ml/10l of calmag every third watering.

I dont have decent ventilation atm, (im on my way fixing it, already ordered a fan.) I would love to get some feedback, since I want to put these in flower but im afraid whatever trouble i have will spiral put of control if i do, LOL!

Thanks in advance, much love,
/B

It's either bugs, a genetic flaw, or maybe you're spraying something on them. It could be nutrient deficiency, but if you don't think so, then look for bugs. If you're spraying, then stop doing it. If it's nothing else then it's probably a flaw of genetics and you can't fix that.

What are you growing in? What pH are you running?

It could be pH related, forgot about that one, but it's important to know that it's nutrient that drives pH so that part has to be understood well, not just pH. I mean, you can't just use pH adjusted water on the next watering and expect the problem to stop. Feeding fert to a plant makes it so easy to screw things up.

I keep the PH at 6.2-ish. I never go above 6.5. I dont need to use PH-down, the nutes buffer the pH down to the values mentioned, and i grow organically. I just recently started adding nutes, since the plants were yellowing off on the lower leafs.. and I built up the dosage SLOWLY. So I can't imagine this to be nute-related. But then again, im no expert.

I got a duct-fan now, together with a couple table-fans, throwung around and pulling out air, so I've got a decent circulation atm.

I grow in soil, light-mix soil. As you can see, the problem is starting to spread to other leaves.. those bleached spots on the leafs become holes after a while. It almost looks like there's something munching on them, but i can't find any pests! Utterly confusing..

Best regards,

slight lack of K. im seeing the same stuff in my room. im only assuming since you seem to have everything else dialed in close. K is always a problem in organics an soil in general.

Hmm Potash you say? Well, that just seems kind of wierd, since I use fish mix, which has a ratio of 5-1-4.. and I mean, last time I fed them they got 2ml fish mix/per litre of water. And they seem well developed you know? I transplanted from 1l pots to 10l pots about 10-12 days ago and the roots are already pointing out from the holes in the bottom of the pots. Doesn't a K-def. Stunt the plant in its growth? Because these babies are still growing. One thing I've noticed also is that after I tried to foliar feed, it got WORSE. A LOT.

But, the edges of the leaves don't get burned like they do when they get overfed. And they are yellowing off slowly in the lower vegetation= N def, right?

So my conclusion is that the humidity is what's causing it. I had very very low humidity in the grow chamber initially, and i think there was some small spots on some if the plants already back then, but they were tiny, and since i had a humidity if like 35%RH I thought it was related to that. But it seems like it's only gotten worse, with time. And now, I have basically optimal conditions, and they're still growing, but some leaves are wiltering and dying like this. So im seriously considering watering pure water for a couple days, plus spray one or two times with water, just to see if it gets worse.. cuz if it does, then I can rule out nutrients, am I right?

Thanks for all the replies guys! Greatly appreciated )

yes, you are correct. If you water only then it should get worse fast. That would rule in or out nutes.
Im not like these other guys , im reading the plant and what you say ......its not PH. You have k in your food, its not going to die from lack of K , it just wants slightly more. If it was full blowd potash def then it would slow down an look like shit , thats not the case. She is just missing a tiny bit of something and i think its K. Mag is the only other logical choice. (going by your plant , not the charts)

Hmm, i see man. The biggest thing that bugs me is, how come it gets worse when I foliar feed? The leaves looked even more f**** up after I foliar fed, and i used a light solution that I also use for newly established clones, and it made it even worse.. I just don't get that. I mean I might have a slight K def. As well, don't get me wrong. But I feel that something bigger is at play here, lol. There is something else going on. Cuz under my 10 years or so of growing, plants have NEVER reacted like this when being foliar fed. Actually a bit scary tbh, since I don't know how to handle it. It feels like the humidity is a culprit, but why? I mean geez, plants in the vegetative phase loves high humidity and "rain", am I right? So why do they wilter, and crumble like this? Doesn't make sense mate! :/ so confusing

They're showing short on K, yet you're feeding K...so if that's the case it's one of 3 things: Too much of another nutrient, locking K out, not enough K for the genetics you're working with or K is being locked out by your pH. Looking at some of your leaves in your second set of pics and the way some of them are twisted, cupped over, etc, would lead one to believe it's pH. If your pH is good going in, then I'd check it coming out and / or check my soil pH to be sure. This is where I'd start. Good luck

Now, Most of them looks like this.. Im gonna take a pH-test on my soil, and the water coming through the pot. I have my doubts that it'll be the culprit; but i guess I need to rule it out first.

This plant seems to be pretty sensitive to foliar feeding. Probably not a good idea. The light green color looks like low nitrogen level in the soil. what soil are you using?

That soil looks wet in all of those pictures. Constantly wet soil will starve the plant of oxygen and cause other issues with nutrient uptake.

Ok, soil test is done.. neutral soil.

Water is 7.8, without nutes. With nutes it goes down to 6.2-6.5

Thanks för chiming in, xtsho! :3 I'll take that in consideration and dry them out a little bit extra. But so far I've only used about 1l every watering, to 10l pots. I let them stay dry for a day or so before I water too, but maybe I've over-done it, i dunno.

The thing bugging me, is that they react bad when I spray water on them.. plants should handle water, I mean!

I use a Swedish soil, called "Hasselfors S-jord", supposedly a very solid soilbrand that has done me well many many times before. Low EC, perlite and humic mix, good stuff.

Hmm, i see polish, but sensitive to foliar!? Just seems incredible, since every plant I've ever grown has loved it. But hey, maybe that's it. Im thinking maybe leaf septoria? Since the moisture is making everything much worse. I dunno, But it feels like there's an external problem you know?

Beat regards

Perhaps. If your nutrient isn't well rounded, meaning many elements, you might consider changing it. Other than that, good luck cuz I have no clue.

I see this on some of my plants it looks a little diff tho but it has always bugged me it happens on some more than others and i tried everything and for me i think its either calcium or using the Qb leds that i have cant figure it out but it does seem to go away in flower and doesnt affect yield but it may be diff soo idk

Well tbh, I've never encountered it before. And I've always used this nute, and it has kicked ass every time. Fish mix+Rootjuice has every nutrient and trace element, and macro that is needed for a good vegetative cycle when growing organic, so i don't think it's related to nutes. I know biobizz can be a little low in Mg and Ca, but I've added it separately so i don't know, I have a hard time imagining it. Thanks for the feedback guys, I'll keep y'all posted, and I'll keep experimenting, I know I will solve it eventually.. just a matter of time. Let's dial down on nutes, and lower light intensity, AND, I'll keep wetting the leafs, without nutes, to see how they react.

Thanks again folks!
Best regards,
/B

CannaCountry said:

They're showing short on K, yet you're feeding K...so if that's the case it's one of 3 things: Too much of another nutrient, locking K out, not enough K for the genetics you're working with or K is being locked out by your pH. Looking at some of your leaves in your second set of pics and the way some of them are twisted, cupped over, etc, would lead one to believe it's pH. If your pH is good going in, then I'd check it coming out and / or check my soil pH to be sure. This is where I'd start. Good luck

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Yes either too wet, too much ph swing between fertilized water and non, temp too low, or the above. Foliar with mg too see if they darken up, too much of either k or mg will lock one of them out.

Have you considered bugs, as polishpollack mentioned? The leaf damage looks like bugs to me. I'm not sure what kind. Have you attempted to check under the leaves with magnification?

II. LOOK FOR PATTERNS: On more than one plant? On more than one plant species? A. Non-uniform damage pattern-(scattered damage on one or only a few plant species) is indicative of living factors (pathogens, insects, etc). B. Uniform damage pattern over a large area (i.e. damage patterns on several plant species) and uniform pattern on the individual plant and plant parts indicates nonliving factors (mechanical, physical, or chemical factors.)

A SYSTEMATIC APPROACH TO DIAGNOSING PLANT DAMAGE: https://agsci.oregonstate.edu/sites/agscid7/files/horticulture/osu-nursery-greenhouse-and-christmas-trees/onn130601.pdf

Yup, as I mentioned above, it almost feels like there's something munching on them, but i dunno.. I'm gonna check them out with a magnifier later too, just need to get my handa on one. Here's some more pics from today:

I've ordered some neem-oil, they'll get their first shower this evening..

Best regards!