Repotting Bonsai with Akadama: Proven and Safe
Akadama bonsai soil
Akadama (Akadamatsuchi) is a bonsai substrate that is indispensable when repotting bonsai. It is a clay granulate with a, as the name already says (Japanese 赤玉土 = red earth), red to reddish brown colour.
Akadama occurs naturally on the island Honshu (mountain Akayi - near Tokyo), is mined there in the open-cast mining and is exported into all world. Akadama is of volcanic origin.
Akadama qualities: Double line and single line brand or Hard / Soft Quality
Akadama is very dimensionally stable, hardly compacts and decomposes only slowly. Depending on the quality of the substrate used, it should be replaced after 2-4 years. During this time Akadama slowly loses its coarseness, the air permeability decreases, the salt content increases and consequently the humidity in the soil increases. Thus the essential advantages are lost - an exchange becomes necessary.
Repotting bonsai - When is the right time ?
- Bonsai soil compactation: Many bonsai soils disintegrate over time and then have to be exchanged.
- If the root mass is too large for the bonsai pot. The roots are then reduced by repotting with root pruning.
- In case of lack of oxygen in the root area. Mostly when the bonsai soil is too fine.
- Pests have accumulated in the soil. Rarely a repotting reason. Sometimes it's a possibility.
- When the soil is salinated, eg. after over-fertilisation with a mineral fertilizer (nutrient salt).
Repotting bonsai - General Information
- The best time for repotting for most plants is early spring (late February to early April). Injuries to the roots can heal quickly.
- Younger and fast growing trees are repotted every 1-2 years. With adult Bonsai (forming is essentially completed) normally a 3-5 year rhythm is sufficient.
Satsuki azalea bonsai repot - Step by step guide
Bonsai root through - with healthy growth - the bonsai pot more or less quickly. Important, tiny cavities in the bonsai substrate are quickly filled. The bonsai soil is compressed. The air and water permeability of the bonsai soil decreases.
However, the bonsai plant urgently needs a well-permeable soil in the bonsai pot. Otherwise first the root growth and later the growth of the entire bonsai would suffer.
Young, fast-growing species (eg. Maple bonsai, Chinese elm bonsai) with strong root growth usually have to be repotted after 2-3 years. Older bonsai, especially conifers, can often spend much longer in their shells. They root through the substrate more slowly.
When repotting bonsai, in most cases a root cut is carried out to reduce the root mass and increase the fine branching.
In this article, we show the basic steps that have to be taken when repotting.
Remove fixation wire
If the bonsai has been properly and professionally potted, the wire for fixing the root ball must be removed before repotting of the bonsai can start. The best way to do this is to cut the fixing wire on the underside of the bonsai pot with Wire cutter.