Nirogen deficiency?

hey all,

New to forum. Have 4 girls outside that were doing fantastic. Up until about a week ago I've been getting a lot of yellowing, leaving falling off, and one plant I'm getting very thing leaves.

I think I'm looking at nitrogen deficiency....but I'm not sure. I've attached some images.

Any help greatly appreciated!

Medium? Watering/lighting schedule? Temps and rh?

Coco blend, fox farm nutriant schedule, 12/12 approx 35-40%

Yea looks like nitrogen and or cal mg deficiency. It happens a lot more in smaller pots for me.

I should almost mention I'm trying for 5.5-6.2 for ph. Average of 6