Coconut coir bricks are composed of three different types of compressed coconut coir. This high quality, low sodium growing medium is an environmentally friendly alternative to sphagnum peat moss. When hydrated with water, CocoTek Bricks and Blocks rapidly expand which saves you time and effort. They can be exclusively used by themselves, blended together or mixed with expanded clay pellets, perlite or topsoil. The brick will break down on its own in three 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.