Some grower's do experience the problem's that you mention with rockwool because they use the wrong application's,they either tend to over saturate it or the ambient tempeture's are too low or unstable,unlike soil,rockwool hold's a lot more water and oxygen and it's very porous,which make's it more sensitive to atmospheric condition's,that could be why the outcome of you're experiment gave you those result's,i started in soil(like most grower's) and used it for a long time,the convenience and low maintinance,not to mention being lightweight and economical as well as the cleanliness,make's it the medium of my choice.i think if you do a little more research,you will benifit from the advantage's of using it. http://www.mellowgold.com/grow/rockwool ....bonbon