BONSAI SOIL
There are many different soil mixtures used to plant bonsai. Bonsai people in Florida, Scotland, Holland, Japan, Canada and California all have different growing conditions and different materials available to make soil mixtures. Most mixtures have one thing in common – they don’t use garden soil. This is because shallow pots don’t drain as well as soil in the garden and as a result the roots can stay too wet and rot!
##Soil PH Soil pH is a measure of the acidity or alkalinity of the soil on a scale of 0 to 14. Neutral is 7, while less than 7 is acidic, greater than 7 is akalai. Soil pH affects the amount of nutrients that are soluble in soil water and, therefore, the amount of nutrient available to plants. Some nutrients are more available under acid conditions while others are more available under alkaline conditions. Most deciduous trees (e.g. maples, elms) prefer soil that is nearly neutral – 6.5 ph. But conifers prefer a slightly more acidic soil, around 5.5 ph.
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Akadama and sand are used for moisture retention. Akadama is slightly acidic
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Lava and pumice are used to improve drainage. Lava has an average porosity of 70-90% (depending a bit on type and size) and is listed as an inert material so no influence on pH values.
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Pumice has an average porosity of 90% and has a tendency to increase pH values slightly. It has the added advantage of weighing much less than lava. Pines and junipers prefer a slightly more acidic soil, so using Kanume (4.5 – 5 ph.) instead of pumice is recommended
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Turface is most commonly used as a soil additive to help improve drainage.
Turface absorbs its weight in water while decreasing soil compaction, which is what you want from bonsai soil. So in that respect it acts like Akadama or Kanume - and is a lot less expensive. Many people successfully use Turface instead of Akadama
