Provides aeration and drainage to the potting mix. Heavier than perlite. 1/3 lighter than sand. It holds vital nutrients in the microscopic surface pores, which helps regulate fertilizer feedings. Loosens the density of heavy clay garden soils, letting in the air and water plants need. increases water retention in light and sandy soils. Holds moisture in the soil, reducing watering requirements, yet pumice will not compact or become soggy. Is inorganic, will not decompose or compact over time, and can be recycled and reused. pH neutral. Does not attract or host fungi, nematodes, or insects.