I never have used Rockwool, and I never did have success with the peat pucks, but haven't tried for many years. I do know that you are supposed to rinse the Rockwool cubes well, with properly ph'd water prior to use. But if you can do peat pucks with success, there's no reason you can't fill a seedling tray or a seedling cup (the black ones are usually free at the nursery) with potting mix, dip the clone, and get the same result. (for much cheaper) :thumbsup: