Higromite is the only growing medium of its kind in the world. Higromite is mined from volcanic deposits colonized by protozoa in freshwater lakes millions of years ago. These unique mineral deposits offer a broad range of trace elements that support microbial activity which enhances root growth, plant vigor and crop yield. Higromite provides several advantages over expanded clay pebbles, coco, and rock wool. It’s high in silica, pH neutral, and has the best moisture retention & release on the market today. Completely reusable, the varied shapes of the rocks promote porosity, allowing more oxygen to reach the roots.