What Is in Bonsai Soil?

The word bonsai means tree in a pot or tray-planted in Japanese.

Bonsai is the art of growing miniature trees in trays or other types of containers. Pruning and wiring control the trees' size and shape. What little soil they grow in should be specifically formulated for their particular needs.

Composition

Bonsai develop by absorbing water, nutrients and gases from the small amount of soil in which they grow. The ideal soil is composed of two basic ingredients: peat or organic matter that retains water and supplies nutrients, and grit that provides drainage and allows air to reach the plants' roots.

Variations

Different bonsai species require varying levels of water and nutrients, such as junipers and pines that require less water than other types, while deciduous and flowering bonsai trees need more water. Soil mixes should reflect these distinctions with more grit added to the soil for pines and less for flowering trees.

Standard

The basic mix for bonsai trees has typically been a 50:50 ratio of grit to peat moss. If peat is not available, use leaf mold or composted tree bark.

Organic vs. Inorganic

Inorganic soil mixes have become more popular with bonsai enthusiasts. Unlike, organic substances, they maintain their structure longer and provide better drainage. These materials include Japanese clay, or akadam, baked clay, or seramis, perlite, and vermiculite. All hold large quantities of water without turning to mush.

References

• Bonsai4me.com: An Introduction to Bonsai Soils
• The Bonsai Site: An Introduction to Bonsai Soils
• BonsaiGardener: How to Grow Bonsai Trees