When should I repot a bonsai?

When should I repot a bonsai? Find out all the information in this post!

Over time, the fertiliser remains and the fine roots that the tree renews end up clogging the soil pores. As a result of these conditions, roots end up drowning and only the strongest survive. The substrate aeration is also reduced, and the drainage becomes clogged, repotting being the only solution.

Even if we used hard-grained soil, which does not fall apart, the soil will still become compacted. On the one hand, the constant supply of organic fertilizer, and on the other, the fine roots that the tree renews will end up reducing the drainage of the soil. In these cases, repotting becomes necessary, as it will favour the growth of new and vigorous fine roots.

If we cannot repot because it is not the season, chemical fertiliser will be our great ally to momentarily maintain the vigour of our bonsai. For this reason, we should know it is a mistake to continue fertilising with organic fertiliser when the drainage begins to decline. Liquid fertilisers, iron chelates, and amino acids dissolved in irrigation water are very effective to ensure the tree stays in good condition until the next repot.

In many bonsai species, roots begin to grow after shoots. New shoots grow thanks to the nutrient reserves that the tree was able to accumulate during the previous season. For this reason, it is important for the trees to stays strong until it is repotting time, and that is why we fertilise more in autumn.

Some example

In this image, you can see how the soil is loaded with organic matter. This is a sign you must repot your bonsai.

Another way to detect the need for a repot is when we look at the colour of the leaves. For example, this apple tree has not been transplanted for 5 years and it is beginning to look exhausted judging by the colour of its leaves.

Now that you know when you should repot a bonsai, check yours and decide if they need to be repotted.

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