What is Akadama Soil?
In the world of bonsai the right substrate makes all the difference in the health and vitality of your trees, so perhaps you’ve heard about “akadama soil.” Akadama is a unique and natural bonsai soil originating from Japan. Composed of volcanic ash, it undergoes a meticulous process of extraction, sifting, and drying. The result is a soil with exceptional water retention and aeration properties, making it an ideal choice for a variety of bonsai & plants. However not all Akadama is the same, and using the wrong type could be fatal to your tree collection.
How does Akadama work?
Akadama is popular for bonsai as its porous nature allows it to retain (and release through cation exchange) moisture and nutrients. It does this while allowing more oxygen in the soil which is vital for root function. Akadama can be used with other ingredients such as pine bark, kanuma, pumice and other organic matter, however this is subjective dependent on tree species, climate region and stage of tree development.
Which Akadama type is best for Bonsai?
Akadama is naturally ‘mined’ and is found at various depths. The upper layers tend to be softer, whilst the deeper layers are harder.
This is crucial to consider when using it for your bonsai soil. A softer mix (which will be cheaper owing to the ease of retrieval from the top layers) will break down quickly and become like a ‘sludge’. Such characteristics can also be found in mock Akadama products. This spells danger for your tree as it is the exact opposite of what you are trying to create – a more porous bonsai mix. The old adage ‘buy cheap, pay dear’ is in operation here. Akadama must be hard, meaning it holds its properties longer and allows for a free draining mix. Water will pass through freely, and oxygen will be drawn into the soil. It is important to buy High Grade, Hard Akadama such as ‘Japanese Triple Line Akadama‘.
The benefits of High Grade Akadama
Whilst Triple Line Akadama is more expensive than commercial grade bonsai mix, there are numerous added benefits. Quality akadama can be reused, as old Akadama can be sieved and potted again if it has retained its form and hardness. Akadama’s characteristics promote tree health and porosity of soil. Nutrients are held longer PLUS there are less weeds and soil borne pests often found in regular soil.
