Hydrotek's exclusive formula, developed for serious growers! A very porous growing media created with long-fibered Canadian sphagnum peat moss including large peat chunks and coarse perlite. ProTerra HDM is designed for crops that require higher air capacity and drainage. Fortified with a well balanced charge of macro and micro nutrients, it includes a wetting agent and is pH balanced with dolomitic and calcitic limestone. Specially designed and developed for high aeration with less weight. Because of its porosity, ProTerra HDM is highly resistant to the formation of algae.