HELP! Yellow leaves

[FlyingHedgehog]

Setup:

I’m growing different auto strains in 30L pots, using soil with varying parts perlite and coco coir and
400W HPS lights. My tap water has a PH of 6.5, I water them approximately every 3 days.

I have an oscillating fan and an extractor fan (good airflow), temperature 27° during the day and 22° at night (18/6 plan)
The plants broke ground four weeks ago and grew perfectly until now. Because of grow space restrictions, I installed a SCROG last week despite it being auto plants, but without lollipopping or trimming.

I used EM-a as a root booster in the second week. Then covered the soil with a thin layer of fertilizer so some nutrients get to the roots with every watering.
Four days ago, I powdered some fertilizer and dissolved it in water to give to the plants. The water still had a PH of 6.3. The fertilizer was Organos, containing 9.5% NO, 2% P2O5, 4% K2O, 1% Mg, 65% OS/MO

Problem:

Since then, my plants have been getting progressively worse. There are lots of yellow leaves, but not uniformly so. All of the following appear:

• Yellow leaves at the bottom - might be understandable because they don’t get much light since the SCROG? (Photo 1)
• Extremely yellow leaves at medium height, weak and curling very strongly (Photo 2&3)
• Spotty or partially yellow leaves at medium height, ‚normal‘, horizontal growth (Photo 4)
• Spotty or partially yellow leaves at all heights that are droopy and heavy (Photo 5)

All my 15 plants are affected in some way. Does anyone have an idea what could be the problem or a solution? I researched it, but the most common reasons for yellow leaves are not really adding up in my case. Nutrient deficiency after the new fertilizer seems unlikely, over-/underwatering as well because I haven’t changed the routine.
Thanks so much to everyone reading this, would be grateful for any advice!
Sarah

[bboyfromwayback]

Auto’s are weird. Your plants look relatively healthy except for the yellow leaves. I’m doing my first auto grow right now and my best conclusion is that they’re just weird. I have one strand that droops and looks overwatered every time I water it, no matter how little water it gets. Then the next day it’s back to normal. I’d remove all the yellow leaves and see what happens. At this point I’d be more concerned with how the buds themselves look and if they’re happy don’t worry about the leaves. That’s just my two cents

[FlyingHedgehog]

Ok, thanks for the reply I'm still worried because there seem to be more yellow leaves every day, but as you say the other leaves and the buds look healthy so I will see how it continues. Thanks and happy growing to you !