Small Sponge Rock – Perlite

Sponge rock, also known by the name Perlite, is a very common ingredient in orchid mixes and for good reason. Sponge rock decreases compaction of mix, increases aeration and retains moisture. Sponge rock is a volcanic glass that expands when heated and becomes very porous. The small sponge rock, #2, is wonderful in seedling and peat mixes.