rock wool is garbage junk no good so on.i have always used rapid rooters they are the best. last batch of clones i bought was rocwool.b4 this i have never had a problem.these things are growing slow as fuck and as a bonus i now have fungus nats.thats another first in my room.notice the gunk that grows ontop of the rocwool this promotes pests. these shops better wise up or they will loose biz.as i for one will never go outside what i know is best again.live and learn i guess.

roc wool is garbage junk that will hurt your crop and cause problems in your grow for sure.