Volcanic stone from GreenGrows Soil is a highly porous volcanic growing medium that helps improve soil structure and growing mixes by increasing aeration around the roots, improving drainage, and retaining a studied portion of moisture and nutrients within the surface pores. It lightens heavy soil, improves the performance of light soil, and supports the stability of the growing medium without rapid decomposition. It can also be reused after proper cleaning. It is a practical choice for growing mixes, planters, grow bags, hydroponic systems, aquaponics, and top dressing, with the appropriate size chosen based on the need for higher moisture or higher aeration and drainage.