Coco coir: also known as a hydroponic growing medium. This is a natural growing medium that can be easily regenerated in hydroponics as well as used in soilless systems.
Perlite: also known as a hydroponic growing medium, is a volcanic rock mined in Mexico and Chile. This volcanic rock can absorb up to 25% of its weight in water and release it slowly over time. When water gets into the stone, the stone expands like a sponge and absorbs the water quickly, leaving the fastest rate of expansion possible. The stone cracks when it is heated above 500 degrees Fahrenheit to allow it to expand more quickly. This rock can be used in soilless mixes because it has absolutely no nutrients in it at all
Rockwool: Also called expanded clay, this is a manufactured product made from the by-product of the paper-making process. It is made in several grades to fit different hydroponic systems and has been used in many successful hydroponic growing environments.
Hemp fiber: also known as a hydroponic growing medium, this is a natural growing medium used in soilless mixes.
Sand: also used in soilless mixes, this is a natural material that can be found on a beach.
Sawdust: also used in soilless mixes, this is a natural material that can be found in a woodworking shop.
Expanded clay pellets. Also known as a hydroponic growing medium, this is a manufactured product made of heart-expanding clay. This is usually used in large commercial settings such as greenhouse operations and smaller greenhouses.
Soilless mix: a combination of various hydroponic growing mediums mixed and then applied to the roots.