Grodan® RWAO3640 A-Ok Starter Plugs™ Plant Starters, 98-CountGrodan A Ok Starter Plugs are designed for seed and cutting propagation prior to "blocking on" into larger growing blocks. The V shape design of the plug discourages tangling of roots between the plugs in the A'OK plug sheet. Come in a sheet that fits a standard 10x20 flat. Grodan Stonewool (rockwool) is made from molten rock spun into cotton candy like fibers and then compressed into cubes, blocks, or slabs. Where other rockwool brand manufacturers