Mini-Blocks 1.5" x 1.5" x 1.5" sit in a tray (flat) without support for easy starting of seeds and cuttings, 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. Three strips of 15 wrapped Mini-Blocks give you 45 total blocks each measuring 1.5" square.