I am looking to improve the number of roots that successfully root into media vs aborting. More often than I would like, a newly growing root, often key to the future of a division or bareroot purchase, hits the media and decides to stop growing.
I agree with instability , and will add that if the medium is dry and absorbent, it can literally desiccate the tips that come in contact with it. I’ve usually only seen that with LECA, but I imagine other materials might do something similar.