An excellent alternative for germinating seeds for root development. This 9" x 18" mat is comprised of sponge-like cubes that can be broken apart individually into 98 individual 1 1/4" squares that can fit into our solid bottom tray. Comprised of 90% organic materials in the form of composted bark and peat held together by a non phototoxic binder that produces a sponge-like cube. This high porosity is the key to a healthy root system and will not compact, providing good aeration throughout the growth cycle. Ideal for starting seeds indoors and also good for most types of plant propagation from cuttings.