It is very important that you use the right type of soil depending on your bonsai type. The soil needs to offer the right combination of nutrients, as well as the right drainage, aeration, and water retention properties.

Akadama

Akadama is Japanese hard fired clay. It is rather expensive and can be difficult to find. It can be substituted with similar fired clays, like turface. Akadama has excellent water retention properties. It will slowly break down over the life of the soil.

Pumice

Pulmice is a lightweight and porous volcanic rock. It has good water retention properties. Pumice is very hard and should not break down.

Lava rock

Lava rock retains water and adds good structure when part of a Bonsai substrate.

Organic compost components

Organic potting compost includes peat moss, perlite, bark and sand. These elements add nutrients to the soil. It does not drain very well, but it works fine if used in combination with akadama, pumice, and lava rocks.

Recommended Bonsai soil mixtures

Each type of bonsai tree will have its own soil mix requirements, so the best is to check what is the best composition for your particular bonsai tree. As a general guideline, the below describe the typical soil composition for the three main types of bonsai trees.

Deciduous bonsai trees

• ½ Akadama/Turface
• ¼ Pumice
• ¼ Lava rock

Pines and conifers

• ⅓ Akadama
• ⅓ Pumice
• ⅓ Lava rock

Indoor bonsai trees

• ½ Akadama
• ¼ Pumice
• ¼ Lava rock