Soil and transplanting

There are some quite different demands to the choice of soil for Shohin- and Mame-bonsai, compared to bigger trees in bigger pots.

All together it can be summed up in two main differences:

1) Shohin-bonsais are living in a very limited amount of soil, and space, and are therefore drying out quicker than bigger bonsais.

2) The soil is filled up with roots from the plants faster than big bonsai, and the therefore the need for transplantation will be more frequent.

Roots pruned.

Roots pruned.

Remember to let the tree dry out, before it is transplanted. It should not be totally dry, but it is important that the soil is so dry that you are apple to remove it without damaging the roots unnecessary. Whet soil will take the finest hairy roots with it, when removed.

Use a chopstick to clean out soil and roots. Don’t let any old earth be that is clay-like and dense in structure, because it will prevent water and air to reach the roots, and they will die.

Let a little amount of the old soil stay, when the tree is transplanted. Especially when transplanting Pines, it is of importance to let some old soil be around the roots. Because the white Mykhorriza fungi is very important to the Pine tree. It is seen as small areas of white hairy lines around the finest roots. But newer let clay like soil, or very compact soil, stay in the pot. It is essential for a bonsai to be able to let the roots breath so to speak. Air is a very important factor of the environment in the pot, in order to keep the roots healthy.

Remember that also the new soil used at the transplanting, has to be very dry. The soil I use for my Shohin are a little bit different, but it also depends on the specie. In general I am always using small lava pieces or Leca pearls, for drainage layer in the bottom of the pot.

For the smallest Shohin (Mame)

The general soil-mix is made of:

70% sphagnum peat

30% of fine-grained lava stones, or small Leca pearls.


For Pines and Junipers:

60% sphagnum peat

40% lava or leca

For the normal Shohin

The general soil-mix is made of:

60% sphagnum moss or peat

40% of fine-grained lava stones, or small Leca pearls.


For Pines and Junipers:

50% sphagnum moss or peat

50% lava or leca

Leca are a hard burned pill of clay, which are totally steady in structure, and retains a good part of air. Lava stones in smaller pieces for Aquariums can be used instead of Leca, or blended together with Leca.

The particle size for a Shohin-bonsai has to be a little bit finer than for bigger bonsais. Just use common sense to evaluate how fine it needs to be.

Remember it is of great importance to keep dust like soil away, to prevent the soil from being to compact. A very dense soil will limit the amount of air, and eventually kill the roots. Like in the case of old soil that is very compact and sour.

I have to mention, that I newer uses Akadama. I find, it is of no benefit for the plants if they are living in an environment, where the humidity of the air is so much lower than it is in Japan. Akadama is good where the air contains a high level of humidity. Akadama is clay, and in the start it is very loose, and holds water rather shortly. But in exchange it provides the roots with a very high level of air. That is excellent, but only in an area with very high air humidity.

And all of a sudden Akadama seems to break down. Thereby it presses all the air out of the soil. With fatal results, when the leaves of the plants cant take water enough from the dry air found in most of Europe. In a dry climate, as in most of Europe, and in places like ours, there is a need for a more water holding soil, so it doesn’t dry out too easily.

You have to do your own experiences, because local water and surroundings makes differences that can be quite extensive. This is just a guideline. Because of the limited room a Shohin-bonsai lives in, it is necessary to repot every one or second year. Depending of how fast the tree grows, and the size of the pot.

It is necessary to repot more often than in the case of bigger bonsai, in order to keep a constant developing of new fine water consuming roots.

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