Pumice is a natural volcanic rock used to improve drainage, aeration, and structural integrity in growing media. Unlike perlite, which is an expanded volcanic glass, pumice is a naturally porous volcanic mineral that retains its structure without additional processing. Its higher density means it is far less likely to migrate or float to the surface of your mix over time, providing long-lasting, reliable aeration throughout the soil profile.
Available in two grades — fine (1–6 mm average) and coarse (7–20 mm average) — you can tailor the particle size to suit your application. Fine grade is ideal for potting mixes, seed-raising blends, and containers where moderate aeration is needed without creating large air spaces. Coarse grade delivers greater drainage and airflow for large containers, raised beds, bottom-of-pot drainage layers, or any mix that requires maximum resistance to compaction. The two grades can also be blended to create a custom particle size distribution.
As a natural volcanic mineral, pumice contains silica and naturally occurring trace minerals, although these become available only very slowly as the rock gradually weathers. It also has a modest cation exchange capacity (CEC), allowing it to retain small amounts of positively charged nutrients and help reduce nutrient leaching—something perlite provides little capacity for. Extremely durable and resistant to breakdown, pumice maintains its structure for many years and can be reused across multiple growing cycles.
