8th week of flower disaster strikes!

[antonix]

hello good people of this forum, i need your help and i am desperate! This is today, mid week 8 of flowering and things don't look good at all! This leaf necrosis has started and accelerated fast in the span of the last 3-4 days.

I have tried to identify the problem using visual cues with online resources but I am unable to make a solid diagnosis.

Do you have any clue what this is and how i can save my crop? So close to harvest and it looks like the end of the world

Growing in Soil
Nutrients: Biobizz BioBloom & TopMax, Plagron Green Sensation
Used some CalMag additive week 6+7
Watering / Feeding every 2-3 days
LED full spectrum panel 250Watts
Sadly I dont measure medium PH. I dont have the knowhow or tools right now to do so

[Gator]

How far away from the canopy is the light

[Ckbrew]

Is it mostly at the top? Looks roasted, maybe to much N for bloom. Back off the lights, use plain water pH adjusted. Here is all you need for pH testing. Dip and read.

https://www.amazon.com/Dispenser-Testing-Range-Intervals-Alkaline-Environment/dp/B0001SR4NM/ref=sr_1_16?crid=1OMC10M7QQL6F&dib=eyJ2IjoiMSJ9.ZgH4JW8O7c6kKZ6q8e2HS8EjGnAkHHTZ7x0yX7Kextrx_qhVrxTj0RIw3mgPvQe0Wc-_IlrZ5DjvwHzBaktysjeXyTaZ9ulhrN_4dAzu6kc1ZOc7msdW4hc1TdyBCDkghBccLf0abbyIBwmt-2XNLeVhva4Dyy5aVLFZRDjDCnnyKOFB84G-cNUbE3l_Jry5idtapxup54kf5GbDWd7synQzDBhyCuJrI8MriJbNbys.2L4PRc04gpLIKYnycVYZvukGpPbV-QShhI1MmBfTG8U&dib_tag=se&keywords=ph+paper+test+strips&qid=1740693944&sprefix=ph+pa%2Caps%2C328&sr=8-16

[9fingerleafs]

Looks like a potassium toxicity. Meaning too much of it. You cannot change the nutrients in the soil in the couple of weeks you got left. You can leach the soil flushing with plain water to try to reduce the rate of leaves burning.

The dead plant matter is not an issue unless it gets trapped inside a bud. So if you see a dead leaf going into a bud you should remove it carefully. But it's not super dangerous anyway. Just flush and wait till harvest. It will all be alright.

If you want to check ph fo the water going in (not very useful in live soil) you should get some pH strips in the range around 7ph. Very cheap and idiot proof.

In soil, before planting, it's common to do a slushy test. Dissolve some soil in a bit of water to test the ph inside the soil. But it can change at any point, being full of bacteria and decomposing matter.

Don't stress out, maybe just go easier on the nutrients in the next round during flowering, soil takes a lot of trial and error

[antonix]

Thank you for your input guys. I can only say its definitely not the lights. After exhausting research, I have narrowed it down to either be excess toxicity of some element or Ph fluctuation in my soil. That doesn't help much as its an inconclusive diagnosis. I removed dying leaves to keep an eye of how the decay progresses. I will keep going with plain water until harvest, I expect that in a week or so. Wish me luck I will need it !