Yellowing/Holes In Newer Growth

[olegren]

Hello, friendly infirmary volunteers! I's me again.

I noticed an issue that I observed in my last grow, and it seems so distinct I'm really curious to see what you more experienced folks might think it is. First the details:

Problem: Some of my newer growth on one plant has these little bulging yellow spots that seem to eventually become small holes. The spots are small and almost seem to bulge a little before eventually tearing.

Medium/grow method: Mother Earth Coco (Compressed) I hydrated, rinsed, screened, and then double buffered in a 2x strength GH calmag solution 8-12 hours per soak. Then loaded the medium 70% to 30% Espoma perilite in 5gallon fabric totes. They're sitting in autopots.

Feed: and supplements used: Outside of the GH Calmag, which I only used to buffer and foliar (Just a water mix) a couple times, these are getting nothing but Prescription Blend nutrients. I am on the first week of veg nutes for them right now. Res is @ 5.8pH & 250 ppm.

water source: Well water run through a home RO system. (12ppm)

Strain/age: Mephisto Strawberry Nuggets @ 25 days

light used: HLG V1 QB @ 260W (3000K). 24/7 for heat. PPFD is currently around 300. (I'm using onboard dimmer and have the light about 26" above tops)

Climate: Average conditions for the last week are 73.9F & 48.1% RH. I have an oscillating fan blowing on them 24/7.

Additional info: Feed solution is currently around 250 ppm and 5.8pH. Its neighbor, a Mephisto Double Grape, is showing no similar signs. I'm LSTing both of them but have employed no other training.

The foliar I've done a few times consists of the GH Cal/Mag (Standard dose) and water. I've spritzed a couple times a few days when I noticed a few random rust spots. I initially did this around day 14 or so; and then started again yesterday when I noticed a few new spots after the initial outbreak seemed to curb.

It's also worth noting that I saw this exact same symptom in one plant from a previous grow. It was a Mephisto cross (CDLC x Forum Stomper) -- But it was the only other plant I've seen this in. That grow was totally different though: Soil, hand watered, etc. That particular plant was 1 of 4 and the only one to see the issue. It stayed fairly localized and never really caused any damage. Structurally, that plant was similar to this one in that it was very thick with leaves and quite bushy.

Thanks in advance for any insights. I've been sifting through photos but can't seem to find anything quite like this. The holes make me think it must be some kind of mite... but not sure how to identify. No other signs if that's what it is.



Here's a photo from a couple days ago; before any signs of this:

 

[Builder0101]

May be physical damage. Plant looks hungry. I'm at 400 PPM at that stage of growth. I'd bump it up to 350 for a few waterings. Monitor them and then go 450...
5.8 is fine but what is your runoff? There are nutrients that can not or are inhibited by that PH. I water in a range typically between 5.9 and 6.3.

 

[olegren]

Thanks. I did get some feedback from another coco expert that mentioned perhaps they were hungry. And to your point the plant is pale; especially compared to the one next to it.

Unfortunately I can't take runoff figures with this since it's a bottom-watered autopot system. Have heard the same on pH though. Maybe I should up the feed a bit and raise pH to 6.0 or so to see if it helps.

 

[Proph]

Thanks. I did get some feedback from another coco expert that mentioned perhaps they were hungry. And to your point the plant is pale; especially compared to the one next to it.

Unfortunately I can't take runoff figures with this since it's a bottom-watered autopot system. Have heard the same on pH though. Maybe I should up the feed a bit and raise pH to 6.0 or so to see if it helps.

Look closely at that plant.. Look at the pics you posted.. Do you see your leaf tips starting to yellow? There is only one thing that causes that. Overfeeding.. Which can lead to lock out. Im heavily leaning towards too much calcium.. If you buffered the coco, there should be no need to use a foliar of calcium, unless calcium is locked out.. Too much of one nutrient can lock out several others.

So too much calcium can cause magnesium issues as well as phosphorus issues.. From what I remember from the prescription blend test is that several of their products already contain calcium.. I'd cut out the foliar and stick to the lower feeds of just the nutrient line.

 

[olegren]

Thanks, @Proph . You are absolutely right that Rx Blend contains Calcium and Magnesium sufficient that the vendor does not recommend additional dosing. The main thread I've been referencing where someone paired these nutes with autopots highlighted one perceived deficiency -- But I believe it was later debunked after the grower realized nutes weren't mixed in the right order. I had started the spray early on when I noticed a few miniscule rust spots on both plants. It seemed to go away; but maybe I created a new problem in the process.

Anyway, I will cease the spray for a bit and see if that resolves the issue. I double checked PPM in my res, and it's actually closer to 220; so pretty low overall. But I do see the tip burn you're pointing out; and can observe hints of the same in my other plant.

Do you think it's worth removing the affected leaves?

 

[Proph]

Thanks, @Proph . You are absolutely right that Rx Blend contains Calcium and Magnesium sufficient that the vendor does not recommend additional dosing. The main thread I've been referencing where someone paired these nutes with autopots highlighted one perceived deficiency -- But I believe it was later debunked after the grower realized nutes weren't mixed in the right order. I had started the spray early on when I noticed a few miniscule rust spots on both plants. It seemed to go away; but maybe I created a new problem in the process.

Anyway, I will cease the spray for a bit and see if that resolves the issue. I double checked PPM in my res, and it's actually closer to 220; so pretty low overall. But I do see the tip burn you're pointing out; and can observe hints of the same in my other plant.

Do you think it's worth removing the affected leaves?

I would not remove the damaged leaves. They are the only visual you have to tell if the issue is getting better or worse. It took me years to learn how nutrients work and how deficiencies express, and it's never to late to start! Nutrients are either mobile or immobile. Mobile means that if there is a deficiency, that the plant can move mobile nutrients from one place to where it's needed. Immobile means that the plant cant move the nutrient to where its needed most if there is a deficiency. Foliars can be temporary fixes for Immobile nutrient issues because the leaves immediately get those nutrients.. But it doesn't fix the issue at the root zone. Immobile issues start showing on newer (upper) leaves first.. Mobile issues start with older (lower) leaves...

The issue with calmag is this.. There is no such thing as a calmag issue.. It's either a calcium issue or a magnesium issue, or both... These two nutrients are completely different, and issues with either are treated differently. Calcium is immobile.. Magnesium is mobile.. Too much of one, locks out the other (see previous chart).. So if you have a "calcium" issue and you apply calcium AND magnesium, at some point the balance will be off and you will start seeing issues with both... I think this is more of your issue than the feed ppm. I think this is the start of a nutrient lock out due an imbalance of calcium and magnesium.

 

[olegren]

Thanks much for taking the time to walk me through all of this. You helped me quite a lot with a previous grow where I had a lockout due to similar over-tinkering. That one was brought on by a mixture of misunderstanding the deficiency/lockout differences and poor watering in soil. I'm also still working towards the organic approach you coached me on; with a couple others' kind mentorship.

Anyway, next steps seem simple enough if I am following you correctly:

1. Stop the foliar
2. Do not adjust feed
3. Observe the existing problem areas to see if it continues to progress

If the problem progresses, I could look into a flush. I have read that it's less than straightforward or ideal when bottom-watering like this, so hopefully it won't come to that.

 

[Proph]

Thanks much for taking the time to walk me through all of this. You helped me quite a lot with a previous grow where I had a lockout due to similar over-tinkering. That one was brought on by a mixture of misunderstanding the deficiency/lockout differences and poor watering in soil. I'm also still working towards the organic approach you coached me on; with a couple others' kind mentorship.

Anyway, next steps seem simple enough if I am following you correctly:

1. Stop the foliar
2. Do not adjust feed
3. Observe the existing problem areas to see if it continues to progress

If the problem progresses, I could look into a flush. I have read that it's less than straightforward or ideal when bottom-watering like this, so hopefully it won't come to that.

Glad to help brotha! The flush would be a last resort. The plant is young enough that it has time to grow out of it if the issue ceases. If it continues to get worse, a light flush may be needed but I don't think the excess or imbalance of cal or mag is extreme right now. Just watch for spreading on both lower leaves and newer growth.

 

[Truth seeker]

Glad to help brotha! The flush would be a last resort. The plant is young enough that it has time to grow out of it if the issue ceases. If it continues to get worse, a light flush may be needed but I don't think the excess or imbalance of cal or mag is extreme right now. Just watch for spreading on both lower leaves and newer growth.

Hey Proph hows it growin? You have helped me out before so thanks again brother and I think I’m having the same issue and rust spots are now spreading even more and I don’t know what to do...any help would be greatly appreciated I can send u pics and explain what I’ve done so far...thanks man