Repotting is a very important part of bonsai maintenance. All pot grown plants become pot-bound after a certain period of time. Repotting a bonsai means pruning the root systems to allow new fine feeder roots to grow. Root pruning does not stunt the bonsai, though you will witness your bonsai lose vigor for atleast 6 weeks.

How Often

You might ask- how often should I repot ma bonsai? The answer depends on the type of tree you are growing. Some trees take five years to become pot bound, while others become pot bound in a year. For example, Figs and Larch are fast growing species that need repotting and root-pruning every year.

You will know your bonsai has become pot bound when you see that the roots have filled up the pot entirely and there are long roots circling the root ball. Also, when you see roots growing out of the drainage hole at the base of the pot you know that it is time to repot and prune the roots. Check the root ball every year in the beginning of Spring. Gently take out the plant from the pot. if you see that the roots are still contained inside the soil, you do not need to repot.

The Right Time To Repot

You cannot repot at any time of the year. The best time to repot is when the tree is dormant. This helps reduce the stress on the tree as there is minimal supply of water and nutrients to the leaves. When you prune the roots when the tree is growing you are actually cutting off the supply of water and nutrients to the leaves. This often kills the tree.

Some people make the mistake of repotting and pruning the roots at the beginning of the dormant season. This means that the roots will remain injured and exposed for a long time as root repairing will only start in the beginning of Spring. Leaving roots exposed and injured for so long often leads to infection and root rot. So never repot a bonsai and prune the roots in the beginning of winter.

The best time to repot and prune the roots of your bonsai is at the end of the dormant season. This way the roots will remain pruned and exposed for a very short period of time. With the growth of new roots, your bonsai will jump back to shape in no time. The exact timing for repotting and root pruning obviously varies according to species and climatic conditions.

So now you are aware about the right time to repot. The next thing for you to learn is how to repot and prune the roots of your bonsai. Once you have mastered that you will have a long and lasting relationship with your bonsai.