Seeds or cuttings are started in these Grodan RWMM4040 mini-blocks, and once rooted, the blocks are transferred to larger gro-blocks or slabs. Mini-blocks can be planted directly into containers for soil gardening as well. For best results, put them on the flat side of the gro-smart tray to ensure good airflow around the cubes. Made from stonewool, the blocks provide even distribution of water and nutrients resulting in quality germination. These mini-blocks are packed in easy to tear away strips and labeled with instructions. Contains 45 blocks per sheet.