IFFCO Urban Gardens Horti-Culite is Exfoliated Vermiculite, sterile, and absorbent material made from a type of mica rock that has been heated and expanded into spongy, pebble-like structure. Vermiculite can improve soil structure and moisture retention in soils that are heavy and compacted, and helps loosen the soil and promote better drainage. Vermiculite is also highly absorbent and can hold water and nutrients in the soil, making them more available to plant roots. Vermiculite also acts as a sterile medium for germination seeds, and can also be used as a mulch, as it helps to retain moisture.