Yellow tips, blotchy yellow spots - Nutes, light, or fungus?

[Lil Dab]

Yes, topfeeding is a no-go for these, which is why I'm in the predicament of flushing or not.

Now I got 2 opinions though - Not enough light, and too much light. I am confused and don't know what to do now.

How much light are they getting I’d be surprised if it was too much light

I understand, but if I keep the PH at 5.8 in the reservoir, it will be at 6.2 already in the autopot trays. If I keep it at 5.6-5.7, it comes out at 5.9 in the trays, which seems fine or not? I imagine the important role is what PH comes into the trays, so I always kept it at 5.6 as recommended by all autopot users who do coco. It's my first run with these things, so I just followed general advice



Did your runoff come out normally? I had to topwater them in the beginning until rinoff a few times after transplant, and it was insanely hard to get any kind of runoff from these pots. I do have airbases which might be the cause. It took ages until all the water fully came out the bottom again, I hated it. That's what scares me about doing a "flower flush" before they hit full bulking stage

Yeah the runoff came out just as usual but I did it regularly hand/top watered till plant was established then put them on the Rez with a weekly flush.

I only ever check my ph at the Rez checking the ph in the trays doesn’t seem accurate cause of the roots being in there

 

[elcoloan]

I only ever check my ph at the Rez checking the ph in the trays doesn’t seem accurate cause of the roots being in there

Agreed it's not too accuerate, but if there is a pH or EC rootzone issue (or even somethin wrong in the resevoir or lines that connecto to the base), you will see the base acting way out of range in both pH and EC in contrast to the reservoir so it can be a useful data point.
Just Out of curisoty I always take note of pH and EC in my bases, and in my best Autopot runs the bases were very close to the resevoir.

I do wonder also about the light, but he said it was 500 at 24 hour so a DLi of around 43... might be a delicate pheno?

 

[PeaceLove&Buds]

Yes, topfeeding is a no-go for these, which is why I'm in the predicament of flushing or not.

Now I got 2 opinions though - Not enough light, and too much light. I am confused and don't know what to do now.



I understand, but if I keep the PH at 5.8 in the reservoir, it will be at 6.2 already in the autopot trays. If I keep it at 5.6-5.7, it comes out at 5.9 in the trays, which seems fine or not? I imagine the important role is what PH comes into the trays, so I always kept it at 5.6 as recommended by all autopot users who do coco. It's my first run with these things, so I just followed general advice



Did your runoff come out normally? I had to topwater them in the beginning until rinoff a few times after transplant, and it was insanely hard to get any kind of runoff from these pots. I do have airbases which might be the cause. It took ages until all the water fully came out the bottom again, I hated it. That's what scares me about doing a "flower flush" before they hit full bulking stage

As for the light, I’m for sure not an expert but 400 ppfd is crazy low to me. Maybe try raising that plant closer to the light if necessary to see if it helps but in my opinion those girls need like 800 minimum right now

 

[PeaceLove&Buds]

Forgot to add that my autopot/coco buddy suggested before I started to plan to use more light because of the constant feeding. Not sure of any science behind it, just that it works for him.

 

[Kazooey59]

I will quickly take some notes, check everything, from PPFD to full DLI, EC/PH in res, EC/PH in the tray of a healthy plant, and EC/PH in the angry ones tray.

Here's every detail:
* Plants in early stages of main flowering cycle, post stretch, around day 46/50
* PPFD currently at ~480
* DLI floating between 39 and 42 depending on location in the tent, cycle is 24/0 as this is what I'm used to with autos
* Reservoir at 6.69PH currently, EC 1.7

* Healthy plant has a tray PH of 6.2 at the moment, which surprised me. Last time it was 5.9 when I checked. EC at 1.6, while reservoir is at 1.7EC
* Problematic plant has a tray PH of 6.45 right now, which also surprised me. Last time I checked, it was at 5.99-6.0PH. EC at 1.7, same as in reservoir

I hope these infos might help in some way, but I'm unsure if it's of any use.

General view into the 4x4 tent with my 4 autos, problematic one is in the top right corner where the colorful sticker is:

As you can see, it all looks just fine. It's just that one plant which seems to be a bit "pissy" about something, and I don't know what it is. I know the symptoms are not deadly at the moment, but more and more leaves on the top get these yellow blotchy leaves, others growing out with yellow bright tips that do NOT turn crispy for a very long time, it just keeps yellowing downwards later on, affecting the serrated edges first, and then later on suddenly causing the blotchy yellow appearance. It's weird!

Edit: Forgot adding the problematic one as of right now, she looks like this everywhere on the top canopy, the upper 25% of the foliage:

 

[BirDMan420]

I literally have the same exact situation just on lower leaves with only 1 plant. Only showed up in preflower and I was wondering if it was light stress, lack of nitrogen for the stretch, lack of P, or overall needing to feed more

Update for this: My girl was hungry. Put them under a stronger light and growth really exploded and I knew that was my tell tale that they needed more food. The one that needed it is the biggest girl in the tent so made sense

 

[Kazooey59]

Well.. I don't know what to do. It's spreading. Heavily.

I have no clue as to what this is. It looks like nothing I have ever had before, and other plants are now starting too.

Notice the sharp contrasts between yellow and green. I've spent 1 week on Google and everywhere now, and not one symptom.. matches. The hell is this?

I'm clueless.

 

[Lil Dab]

EC seems little high which would cause the burnt tips? I think it looks like a K issue but don’t know for sure have you tried adjusting the feed to see what makes a difference?

@Mañ'O'Green might have a better idea as to what’s going on

 

[Kazooey59]

EC seems little high which would cause the burnt tips? I think it looks like a K issue but don’t know for sure have you tried adjusting the feed to see what makes a difference?

@Mañ'O'Green might have a better idea as to what’s going on

The weird thing is, that this is only happening at the top of the plant. The bottom of the plant is 100% healthy. That's what is absolutely confusing me in each and every way. The plants are healthy, they only show this on the top of the canopy, with a few lost leaves here and there in the upper 25% of the canopy showing these symptoms too. I think a K issue starts at the bottom, or? This is all starting at the top of the plant, but not "on new growth", straight up only on the top. This calls for light burn, but with 400ppfd in flower.. absolutely impossible. I am now running 750-800PPFD at a 20/4 cycle (autoflowers), but it's still worsening once again.

2 out of 4 plants now show these symptoms, with one being severely affected, the other slowly starting. Plant 3 is generally turning yellow everywhere on top, but not in this sharp contrast kind of way, more of an even yellowing / lighter green everywhere on the top nodes. The 4th plant is 100% healthy and doesn't care in any way.

Plant 2 with similar symptoms as the severely affected plant, just way less, but it's starting:



Plant 3 which is generally yellowing everywhere and I don't know why:

 

[Lil Dab]

I think a K issue starts at the bottom, or?

I don’t think so if it’s a lockout issue