Pingman,
I started some
seeds in rockwool cubes (the little ones with the holes). When the seedlings were a few weeks old I put them in the 11 plant system surrounded by growrocks. It will work. I wont do it again though. The rockwool holds LOTS of water. You may end up loosing some plants to root rot. Some of mine are growing great. Some died (more than percentages say should).
From now on I start seedlings in a seedling mix. Then in a few weeks, depending on plant type, they go into a hydro unit.
CM