Akadama (赤玉土, akadamatsuchi, red ball earth) is a naturally occurring, granular clay-like mineral used as soil for bonsai trees and other container-grown plants. It is surface-mined, immediately sifted and bagged, and supplied in various grades; the deeper-mined grades are somewhat harder and more helpful in horticulture than the softer, shallow-mined grades. Akadama may also act as one growing medium component when combined with other elements such as sand, composted bark, peat, or crushed lava. The color darkens when moist, which can help the grower determine when to water a tree.
While akadama is more costly than alternative soil components, it is prized by many growers for its ability to retain water and nutrients while providing porosity and free drainage. For all of its qualities, many bonsai growers consider the cost of akadama prohibitive or unnecessary. Still, other growers claim that when subjected to cold and wet climates, the granules progressively break down into smaller particles that inhibit drainage, an unwanted characteristic of bonsai soil. This problem can be avoided by incorporating sand or grit in the soil mix or using the deeper-mined, harder grades.
Specifications
- Fine 1-2mm / Coarse Grade 3-6mm (per particle, and some fine dust around 20%)
- pH 6.9
- packed in a resealable paper pouch
- does not expire
- naturally mined in Japan
Uses
- Mix as potting mix amendment for plants or used alone.
- Potting mix/soil topper
- Bonsai mix substrate
Advantages & Benefits
- changes color depending on moisture content
- holds nutrients well
- does not break easily, very long usability, up to 2 years
