Perlite Medium Premium Soil Expanded Plant Growing Media Plants HydroponicsMedium Perlite is a light, hard, aerated, white mineral, formed from volcanic glass, used in potting mixes to add open and porous drainage, provide aeration to plant roots and hold oxygen, a little moisture and nutrients from soluble fertilisers. Finer to medium perlite is used for in quality seed starting mixes or rooting cuttings as the drainage provided encourages rapid root production. Excellent for succulents and orchids. Medium perlite can also