â€œWhat Is Bonsai Soil?
Bonsai â€˜soilâ€™ is a mixture of organic and inorganic compounds that provide a suitable growing media for the cultivation of bonsai trees within the confines of a bonsai container. A bonsai container or pot is an unnatural and restrictive environment that, consequentially, requires a very well draining soil mix to maintain a healthy bonsai tree. Bonsai soils that work well in a specific set of environmental conditions, may or may not, work well in the specific microenvironment of your backyard. So, it is recommended that you speak with your bonsai supplier or another local bonsai enthusiast that has experience growing bonsai in your locale.
What Kinds of Bonsai Soil Are Available?
There are many kinds of bonsai soils available for sale from your local bonsai supplier, but the Japanese soils are, in my humble opinion, of the highest quality and consistency. They are composed of clay granules that have been heated at extremely high temperatures, so that they will resist compacting and will maintain their structural integrity for long periods of time. The Japanese soils include: Akadama – general purpose bonsai soil that is suitable for most deciduous trees; Kanuma – a yellow colored Japanese soil from the Kanuma region of Japan that is great for azaleas & acid loving bonsai; Kureyu – a soil that is suitable for most conifers.â€
â€œWhat Type of A Soil â€˜Mixâ€™ Should I Use?
There are no â€˜absolutesâ€™ in bonsai and soil mixes are no exception. There are, however, some general soil guidelines that work well for certain types of bonsai trees. All of these mixes contain some combination of the same three major components: grit, organic, and loam. Grit, also called aggregate and sand provides vital drainage for the soil mix. Organic, which is peat moss, pine bark, and leaf mold, provides water retention qualities for the soil mix. Loam, is a combination of sand, organic and clay, sometimes added by portion to augment the specific needs for a soil mix.
Is Using The Proper Soil Important?
Yes. All things in regards to bonsai are interrelated: environmental conditions, water, the time of year, fertilizer use, pruning practice, light, shade and soil. So, using the proper soil is important for growing healthy bonsai trees.â€ â€œDeciduous bonsai soil mixes should be â€˜approximatelyâ€™ 60 percent organic material to 40 percent grit and an alternative soil for deciduous trees is the Japanese Akadama. Azaleas and rhododendrons bonsai soil mixes should be â€˜approximatelyâ€™ 50 percent organic to 50 percent grit and an alternative soil for acid-loving trees is the Japanese Kanuma. Conifers bonsai soil mixes should be â€˜approximatelyâ€™ 30 percent organic to 70 percent grit and an alternative soil for conifers trees is the Japanese Kureyu. Indoor or Tropical bonsai soil mixes should be â€˜approximatelyâ€™ compromised of 70 percent organic to 30 percent grit. REMEMBER – local climactic conditions will help dictate what type of soil mix you should use for successful bonsai in your particular locale, so be an informed enthusiast.â€ â€œIt is important to use both round and sharp shaped particles when mixing the components for your bonsai soil. The reason for this is that round components, which do not compact, provide good aeration, however, they allow a tree’s root tips to grow unobstructed and this encourages upright and very strong top growth – an unwanted characteristic for bonsai culture. On the other hand, sharp shaped components, which do have a tendency to compact, interrupt the passage of a tree’s new root tips, forcing them to divide, thus resulting in varied shoot growth and more sideways top growth, which is a positive growth characteristic for bonsai culture.â€
â€œWhat Is Bonsai Soil?