Are you watering all of them by hand watering? If so man that's seem back breaking an time consuming. Especially if there getting hand water daily I myself is growing on coco in 2 & 3 gal fabric pot.
Idk what I'm doing for it not too root. I'm using rapid rooter plugs ph water at 6.0 with 300ppm. Rootech gel, dome on with no vent open light 18/6 315w cmh in with my mother's tent. Been 2 week with no roots should I toss away an start a new batch
I'm currently growing in coco with advance nutrients ph always stay in 6.0-6.5 but I always test my ph an ppm. If you're looking for some good Ph and Ppm pen I suggest these.
PH PEN...
Looks like you need to feed it more often you want Coco to be saturate so water daily. Dont treat it like soil its hydroponic so water 1 or 2 time daily. That's the reason why your leaf are yellowing