Coconut coir bricks are composed of 3 different types of compressed coconut coir. This 1.4 lbs. (650 g), high quality, low sodium, sterile growing medium is an alternative to sphagnum peat Moss and absorbs great amounts of water, lowering watering frequency. When hydrated with water, bricks and blocks rapidly expand which saves you time and effort. They can be exclusively used by themselves, blended or mixed with expanded clay pellets, perlite, or topsoil. The brick will break down on its own in 3-years. Better still, you can run it through a chipper and amend your soil with It. Incredibly strong, it makes a better candidate for use with enzyme products that convert roots to biomass.