Pumice Substrate 4–8 mm (medium grain) for Bonsai

Lightweight and highly porous, pumice (pumice stone) with a medium grain size of 4–8 mm provides excellent drainage and superior aeration, preventing substrate compaction and supporting the formation of fine roots. The particles absorb some water and release it gradually, maintaining an optimal balance between moisture and oxygen.

An inert volcanic rock, peat-free and salt-free, pumice has a near-neutral pH and does not break down easily over time. It can be used as a 100% substrate for rooting or as a component in modern mixes (akadama, lava, kiryu), offering structural stability in the pot without floating during watering like perlite.

Recommended for indoor and outdoor bonsai, cacti and succulents, as well as a drainage layer at the bottom of the pot, improving air circulation and reducing the risk of root rot.

Product Details

• 🧱 Type: Pumice (pumice stone) — inert volcanic rock

• 🔹 Grain size: medium 4–8 mm

• ⚖️ Key properties: high porosity, excellent drainage, strong aeration, does not compact easily

• 🧪 pH: near-neutral; minimal nutrient content — requires regular fertilization

• 🏡 Suitable for: bonsai (deciduous & conifers), cacti & succulents, drainage layer, improving heavy soils

• 🧰 Recommended use: 100% pumice for rooting/pre-bonsai; in mixes — deciduous 1:1:1 (akadama:pumice:lava) or conifers 1:1.5:1.5; rinse/sieve before use to remove fine dust.