there fine.. at least I think there better then rockwool. the plug will defiantly degrade long before the rockwool
just know sometimes thee root does not penetrate the rooter, and just grows up out of the rooter, if that happens, just rip the plug and put the stem between the sides you just ripped..
Thank you for the heads up!The taproot will blow through the RR in a few days. I would plan accordingly.