Soil

With re-potting comes the need to replenish my stock of Bonsai soil. Growing small trees reduces the need for large quantities of soil so I can buy commercially packaged soil and with a few additions, create the medium that I need.

There are 3 main qualities necessary for a good Bonsai soil:

• Drainage
• Moisture Retention
• Aeration

Drainage

Being that the trees are confined to a small pot, water can easily collect and eventually rot the tree roots. The soil should allow water to quickly drain through and out the drainage holes of the pot.

Moisture Retention

Even though water drains quickly through the soil, the soil needs to stay damp and not dry out too quickly. Moist soil allows the roots to get the water they need without harm.

Aeration

Lastly, the soil can become compact from normal watering if there isn't an element to the soil that helps to loosen it. Roots need air and space to develop properly.

In order to achieve these goals, it may be necessary to create a custom mix of ingredients to make a growing medium for trees to thrive.

My mix:

• Commercial packaged soil (TinyRoots All-Purpose Blend)  50%
• Akadama  25%
• Lava rock  25%

The TinyRoots blend makes up the balk of the soil and provides a good base for the organic component. It has mainly compost mulch and gives the trees the essential nutrients and soil structure. This soil also drains well while retaining some moisture.

Akadama is a clay-like soil used for bonsai in Japan. It occurs naturally but may be further dried. This element also helps in moisture retention while its larger particles loosens the soil allowing air to flow.

Finally, the lava rock gives the soil a courser texture to help with aeration and root development. Overall, this soil mix has worked very well so far. It's a simple mix with easy to find the ingredients and satisfies the requirements of good bonsai soil.