So I seem to have clones take better in jiffy pelets. If I use jiffy pelets the roots come out of them with in 7 days, then I tear off the fiberglass screen and plant. The rockwool cubes are bigger, but I have some clones (in rock wool) that are on day 15 and I can't see any roots. Do I need to prepare the rockwool other than soaking it in distilled water. Is this normal?

I am using rooting powder and kelp spray, 24 hour cfl lighting

You need to soak rockwool in ph 5.5 water. I believe it's too alkaline otherwise.