Vermiculite helps to aerate soil while simultaneously retaining water and nutrients, which it then releases over time. Vermiculite is therefore useful in seed sowing and propagation . It can also be added to house plant compost
clay mineral similar to montmorillonite in structure and, in some cases, composition. Vermiculite is typically formed by the alteration of biotite, and it occurs both as large pseudomorphs replacing biotite and as small particles in soils and ancient sediments.