Simple guide to mix bonsai soil
What's important for bonsai soil is Water-holding capacity, Air conductivity and Drainage.
- Water-holding capacity - How much water the soil can absorb. Soil needs to have high capacity of this. This also helps the soil to keep the nutrition when added.
- Air conductivity - The soil has to have room for the air to go through in the pot to keep the plant healthy.
- Drainage - The soil needs to have high drainage at the same time.
To make a mix of bonsai soils, The soil must accomplish all those 3 above.
High water-holding capacity
High air conductivity
No nutrition and slight Acidity
Good water-holding capacity
Higher air conductivity than akadama
Higher Drainage than Akadama
More like pumice than soil.More acidity than akadama and no nutrition.
And some people add other soil that has nutrition, and some people don't but they fertilize using other source to add nutrition to the soil such as regular fertilizer (powdered, liquid or solid types of fertilizer)
soil recommendations are to buy small and hard grain. Small grains are a lot easier to use and can be fit to many other purpose such as propagation and other gardening soil mix,etc. And they must be hard for bonsai soil if they are used as a main part of the mix so they won't break easily in the pot. If the main soil is soft, it might break soon and causes the bad condition such as bad drainage, poor water/nutrition absorbancy.
So these two soils are the most common soils to make a mix of bonsai soils because they cover all the aspect that are needed to be bonsai soil.
The ratio to make a mix is up to the plant favorite. If they like more/less acidity put more/less kanuma soil. But mainly as bonsai soil mix, The ratio of akadama is more than kanuma.
a lot of shops have akadama but not many have kanuma and dallasbonsai.com has them both and very reasonable price.