Help with leaf necrosis diagnosis

Hello there!

I have browsed the rollitup forums for a while now, but this is my first time posting.

I have a number of plants growing in a greenhouse in flowering stage. I've had a multitude of issues including broad mite infestation, various deficiencies, etc. One plant has black necrotic areas on some leaves, the only plant doing this. What is it? Can anyone help me identify the problem? Pics below.

Soil
Flowering stage
Organic fertilizer/soil build
Various strains that I don't know 100% what they are, but the one affected is the most indica dominant

I was thinking phosphorus deficient, but those cartoony pictures never help, at least for me. What I've seen of p deficiency is that the darkening starts near the main leaf vein, inside the leaf rather than on the edges and moves from there. My leaves are most definitely displaying the opposite, darkening from the edges into the middle. Also, sorry I didn't say this at the top, but these are newer leaves, probably the 3rd set down from the top of the buds. Being a mobile element I thought phosphorus would show in older leaves first?

Is this still phos deficiency or is there another problem associated with edge-in burning like this?

even more difficult to repair

now you cut it off ..?

use the forthcoming leaves as a control point

and as for the organic mix

more details is good

These guys are monsters I don't mind pulling a couple leaves to take pics.

Hoping to get more input on this!

What did you use to control the broad mites? My guess is its damage from that. The veins look awfully healthy and green too me to be a P issue.

I used mostly neem oil with Safer brand insecticidal soap, applied as a foliar spray as well as soil drench maybe 4 times over a month. I also used one application of Mighty Wash. Because I didn't really isolate trials, I have no idea what worked and what didn't. The mites got hit hard, but they are still around in little pockets.

This plant in question was hit hardest by the mites and still have a couple colonies hiding on leaves here and there. They're so tiny I have no way of completely removing them!

But good to know that it could possibly just be mite damage.