Hi @Andi_M8 , I have 3 possible issues for you.
Possibility 1. Magnesium deficiency
Possibility 2. Potassium deficiency
Possibility 3. pH problem
I don’t know if and if so how much magnesium you’re giving, but a pinch of Epsom salt should prevent it from getting worse if that turns out to be the problem.
Potassium deficiency can be caused by too much nitrogen, but I don’t know your fertilizer and feeding schedule, check to see if that applies so you can counteract it.
For a pH problem in the substrate, simply test it; if it’s fine, you can rule that out.
I hope I was able to help you out. Best regards
But do you have thrips in the grow tent?
You need to check the runoff pH when you water. Only that can tell you what problem you have…
Thanks for now. I’ll measure the drain. I’m using organic Green House Feeding fertilizer. Everything should be in there for the most part. But we’ll see.
How do you measure pH from runoff?
With organic fertilizers, the runoff won’t help you. You should add some soil to distilled water, mix it up, and wait until the particles settle, then you can measure the pH.
I think you’re right, besides, he has spider mites or thrips on the leaves
Potassium (K⁺): It is the main magnesium blocker. Excess potassium fertilization drastically slows down magnesium uptake by the plant.
Magnesium is the central atom of chlorophyll (essential for photosynthesis), so blocking it causes yellowing between the veins of the leaves (interveinal chlorosis)
I ordered something for thrips. Dumb to grow indoors in the summer, but that’s just how it is sometimes. Thanks for your help