I was curious about which medium would be quickest/easiest when I took my first set of clones about a month ago. I used stone wool, peat pucks, seed soil and the little peat pots. I don't have one of those cool cloners so I stuck with those 4 mediums. By far the quickest rooting was the soil, followed closely by the peat pots, then peat pucks and lastly the stone wool.
I hadn't considered possible bugs in the soil then so it was probably beginners luck that I avoided them this time. Won't be risking it again.
I wondered if perhaps because the stone wool is quite dense compared with the soil-like mediums that the roots took longer to appear? - could make the roots stronger though.
All the clones rooted in less than 2 weeks and are now veging happily *touch wood*