Pumice (pumice stone) is available in two particle sizes: fine (1–3 mm) and medium (3–6 mm), both in 40 L bags. It is a natural, porous, and very lightweight volcanic rock that adds drainage and aeration to the growing medium without compacting over time. The difference between particle sizes does not change the chemical properties, only the particle size and therefore the crop or system where it is best suited.
Comparison | Pumice stone: how to choose the right variant
