Three major components make up the structure of this soil: peat moss, perlite, and granite sand.
Peat moss is composted sphagnum moss. Its major function is to provide cellulose and humus for the microorganisms and plants. It is also a dispersing medium for the major (N, P, K) and minor nutrients.
Perlite is a volcanic glass that is totally cavitated or porous. Its holes and tunnels allow air and water to easily penetrate the soil. Allowing air into the soil is very important because microorganisms breath oxygen. The more air they can get the more active they can be. The more active microbes are, the more raw materials they can supply to the plants.
The third component is the granite sand. Granite sand is produced by the erosion of granite outcrops. The particles of sand are shaped like boulders rather than being flat sided and sharp edged like builder’s sand. These round boulder-shaped particles do not interlock the way sharp sand does. As a s a result, Thunderhead Soil tends to resist caking, a major problem with most potting soil. Granite sand produced by erosion enables this soil to be used indefinitely. Thunderhead Soil can be reused anywhere for as long as you care to garden.