Coco.....my mortal enemy. I know ZERO about coco. I swear that looks like a ph issue to me. Most of the time my kids crack looking normal.....and then funk up later.

I've always had the questions of this....are Rapid rooters hydro or soil? So are you supposed to use soil ph or hydro ph with them?

I've always used regular water when things are in RR....ph approximately 6.6.....not r o or distilled but I HAVE put them then into my hydro setup at baby age and then begun watering them with something along the ph of 5.7 and they do fine as well.

That just LOOKS like a ph issue to me. Perhaps try watering your kids with normal water but ph'd to 6.5-6.6 and see if it makes a difference.

There shouldn't be a nute issue at this stage....it has to be ph somehow.

STINKY!!