Could be just calcium deficient, or could be cal and magnesium, or could be pH off. Leaves look dark like they don't want any more nitrogen, so the 'deficiency' could actually be a lockout from too much of something. To test the calcium theory, I would do a foliar with CalMag. If the issue is calcium or magnesium, you will see improvement quickly. If not, then you can move on to trying something else, but in a day or two instead of several days or a week.
I wonder if the addition of more nitrogen (from the calmag) would be counter productive since its already running dark.
Aye, that is why I was thinking foliar to avoid the chance of lockout in the root zone. One day, someone will make a calmag product that is not chock full of nitrogen, and we will all rejoice!
https://www.aurorainnovations.com/calmag By creating a product free of added nitrogen, phosphate, and potassium, we give you control to supplement as needed without affecting primary fertility input ratios. Roots Organics CalMag is ideal for fast-growing and heavy feeding plants
BB nice find! I didn't know about it. Probably going to buy some and use it in our foliar when we need calcium in the spray.