Diatomite Rock is a naturally mined mineral composed entirely of the sketetal remains of trillions of microscopic, unicellular plankton called diatoms that is indefinitely stable and non-compactable. Diatomite Rock permanently improves the structure, drainage and oxygen exchange of heavy soils and horticultural growing media. The porous aggreagate particles wet rapidly and will absorb greater than 100% of their own weight in water, acting as a reservoir for plant available water (PAW) and nutrients. Fine to medium particle size (2-7)