Bonsai Substrates and Their pH
The choice of substrate is a fundamental aspect in bonsai cultivation, as it directly influences the pH of the root environment. Different substrates possess varied pH levels, thus affecting nutrient availability and the health of the tree. Here is a list of substrates frequently used in bonsai, with a description of their pH and characteristics.
A. Akadama
pH: Slightly acidic, about 6.5. Characteristics: A Japanese clay substrate, very popular for its ability to retain water and nutrients while providing good aeration.
B. Kanuma
pH: Acidic, about 4.5 - 5.0. Characteristics: Ideal for azaleas and other species that prefer acidic soil. It is a light and porous substrate, promoting acidity and moisture retention.
C. Pumice (Pumice Stone)
pH: Neutral to slightly alkaline, about 7.0 - 8.0. Characteristics: Used to improve drainage and aeration, pumice also retains nutrients and moisture, making it useful for most bonsais.
D. Black Lava
pH: Slightly alkaline, about 7.5. Characteristics: Excellent for drainage and water retention, black lava is often mixed with other substrates to improve soil structure.
E. Peat
pH: Acidic, generally below 6.0. Characteristics: Often used in mixes to increase substrate acidity, peat also helps retain moisture.
F. Pine Bark
pH: Slightly acidic, about 5.5 - 6.0. Characteristics: Used in mixes to improve water retention and aeration, while providing a slight acidity.
G. Universal Potting Soil
pH: Neutral, around 7.0. Characteristics: A basic substrate that can be enriched or adjusted to meet the specific needs of different bonsai species.
Each type of substrate brings its own advantages and disadvantages depending on the bonsai species, climatic conditions, and the preferences of the cultivator. The key to successful cultivation is understanding the specific needs of each bonsai and choosing or adjusting the substrate accordingly to maintain an optimal pH.
