Substrate
Kanuma Acidic Bonsai Soil, 3-5mm, 5L
Acidic Japanese pumice. Suits azaleas, satsuki, cacti and succulents.
AU$44.95
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Kanuma is a soft, acidic Japanese pumice and the standard potting medium for azaleas and satsuki, which need an acidic, free-draining root zone. It also suits cacti, succulents and other acid-loving plants. Light and easy to work with; use it straight or with a little pumice for extra drainage. Sifted 3-5mm. 5 litre bag.
How much do I need?
Approximate fill, measured as pot length × width × depth. Allow extra for a drainage layer in deeper pots.
What kanuma is
Kanuma is a soft, acidic volcanic pumice mined around the town of Kanuma in Tochigi, Japan. It is light and porous, holds both water and air, and is naturally acidic, which is why it is the standard potting medium for azaleas in Japan and elsewhere.
Which plants it suits
Azaleas and satsuki azaleas are the main use: they need an acidic, free-draining root zone, and kanuma provides both. It also suits cacti, succulents and other acid-loving plants. For trees that prefer a neutral mix, use akadama or Sakadama instead.
How it compares to akadama
Akadama is close to neutral and suits most species; kanuma is acidic and softer. The two are not interchangeable: for azaleas and other acid-loving species, pot into kanuma on its own rather than blending it into an akadama mix. Kanuma is also lighter, so larger pots stay easier to move.
How much a repot needs
As a guide, a 20 × 15 × 6 cm pot takes about 2 litres and a 30 × 22 × 8 cm pot about 5 litres, so a 5 litre bag repots one medium azalea or several small ones. The fill table above lists more sizes.
Using it
Use it straight for azaleas and satsuki, or add a little Japanese pumice for extra drainage. Water gently after repotting: dry kanuma is light enough to float until it wets through.
