This is so I have a better understanding. @kellydans @Budz @OlyBoy98503 @Low @Deepsix
I am a little confused regarding the conclusion it is primarily related to NPK deficiencies due to under feeding. If this is the case I would think the lower leaves would show more evidence of deficiencies. NPK are mobile nutrients and will transport to sustain new grown. I see more deficiencies in the upper leaves leading me to think it is more related to uptake of immobile nutrients. Which in turn is often the result of pH swings or pH that is either too high or low.
There are lots of tables out there summarizing impact. This one is easy for me to follow /make sense of
I ask this because I have been experiencing similar issues with a couple of plants. In one case I was able to save the plants and get them to a decent harvest. In another, my reaction was inadequate and much too late and I had to harvest 2 - 3 weeks early.
If interested you can see them at the end of Let’s Grow Some Purple Kush