Perlite looks and feels like little bits of polystyrene but is actually made from superheated, expanded, volcanic glass. It’s sterile, lightweight, easy to handle and long-lasting. It’s neither alkaline nor acidic.
Perlite’s expanded nature means it is extremely porous, therefore absorbs water, but also improves drainage and aeration, providing a plants roots with the oxygen they need to grow and helping to prevent root rot. It is ideal to mix with other mediums to ensure water drains freely. Perlite is particularly useful in plant propagation for cuttings and also for sowing seeds.