Stonewool is a state-of-the-art growing substrate preferred by hundreds of hydroponics gardeners. Seeds or cuttings are started in these Grodan Mini-Blocks and, once rooted, the blocks are transferred to a larger piece of stonewool. Mini-Blocks can be planted directly into containers for soil gardening as well. Two strips of 12 wrapped Mini-Blocks give gardeners 24 total blocks each measuring 2"square. Grodan stonewool is known for its quality, consistency and performance.