Transplanting is the removal of a plant, including its roots, from where it was planted. This always presents a risk to the plant, so you should never repot a bonsai for the sake of it. Look at your tree and it will give you some clues as to whether or not it needs a transplant. many people wonder when to transplant a bonsai so that it can grow properly.
For this reason, we are going to dedicate this article to telling you when to transplant a bonsai and what aspects you must take into account to do it well.
When to transplant a bonsai
By transplanting we also renew the strength of the tree and favor its growth, which is very necessary for bonsai, since to form them they have to endure tasks such as pruning, pinching, leaf removal, very demanding plant practices. Therefore, it is recommended to transplant every 1 or 2 years for a young or mature tree, or every 3-4 years when it is already a mature treeas an additional maintenance task.
The best time to transplant is when the tree begins to sprout after a winter dormant period. In this way we will take advantage of the moment when the roots begin to grow and we will avoid the risk of frost, which is more pronounced in potted trees.
Substrate for transplant
The main characteristic of the best bonsai soil is that it drains sufficiently, allowing pores to develop so that the roots can breathe. For it It must be a substrate with a large and hard or semi-hard grain that takes time to decompose.
When making a mixture, we must anticipate that it must last at least as long as the bonsai can remain in the same pot without falling apart. To do this, combine a semi-rigid substrate like akadama with a harder substrate like limestone or paulownia.
- Trees of feeble leaves: 90% akadama + 10% pumice
- evergreen: 80% akadama + 20% pumice
- Conifer: 20% akadama + 80% pumice
- Olive: 40% akadama + 60% pumice
These substrates are inert soils that do not provide nutrients, so in addition to irrigation, adjustments are required by the user due to high drainage. The task is a bit trickier for beginners, so you might as well start with terrabonsai, a prepared mix of peat, coir, volcanic rock, and akadama that holds more water and provides nutrients.
The moment you discover your bonsai will determine the granularity to use. For young trees that are just forming, a coarse grained growing medium is suitable to promote strong root development, while a fine grained growing medium or small grained growing medium will be suitable for older trees to control fine root development and so on. Control tree growth.
The size of the pot should be 2/3 of the total height of the bonsai. If the pot is too big, it will take longer for the soil to reach the temperature necessary for root growth. After transplanting, there will still be some areas that have not been occupied by the root system in a wet state for a long time, which will cause the root system to rot.
How to transplant a bonsai
During the transplant we will remove the old soil and cut the roots to regenerate them, removing those that are in poor condition and the oldest roots, these are different from the finer roots that are the ones that interest us because there are many darker colors
We can cut 1/3 of the roots that were in the potbut by cutting so many roots, we also have to cut a similar number of twigs to balance the strength of the tree.
Although we are going to use a specific substrate for our bonsai that drains well, if we pass it through a strainer or sieve before using it, we will eliminate the slightest dust that can clog the pores.
We take the tree out of the pot (if the substrate in the pot is too tight, we can remove it with a spatula) and look at the type of soil. If it is a granular substrate, the root ball is too wet for us to handle, so we let it dry so as not to damage the roots, so the soil will fall more easily. If the substrate is very viscous, soak it in water for 24 hours to soften it and let it separate by spray cleaning.
Removing the old soil from the center of the root ball is very important because normally we will be using another type of substrate, the roots will find two different media during their growth process, with different drainage and moisture retention, which will be very difficult for them. They find it difficult to live in these different conditions.
If the substrate that we are going to use is of the same type as the existing substrate, and the degradation is not too severe, we can only remove a third of the entire root ballincluding the top, bottom and sides. For this operation we will use a root spreader or even a very sharp bamboo skewer. We will comb the roots working towards the trunk.
Once the roots are arranged, we will try to balance their growth, pruning the thickest ones more and the thinnest ones less (as we can the branches). We will take advantage of this moment to eliminate the dead or damaged roots and correct the incorrect orientation of the root, using concave pruning shears to make sure the cut wound heals well.
We will remove the roots that grow downward from below and support those that grow to the sides. This is a very important time in the formation of the nebari (root collar), as we only get a chance to do this every few years. During this operation we must prevent the roots from drying out in contact with the air, for this we can spray them with water.
Preparation and filling of the pot
The pots have holes in the lower part to facilitate drainage, but in order not to lose the substrate, we first have to cover them with some grids, we will fix them with wire hooks, we will pass them in a U shape, we will take them out of the pot from the inside towards the outside of the mesh, then fold the ends in, gluing them to the bottom of the pot
In addition, we will prepare some wires to go through the same holes (unless the pots come with holes for this purpose), this will allow us to fix the tree in the pot and facilitate its rootingavoiding movements that can break it. Fragile new roots.
At the bottom of the pot we will place a drainage layer made up of coarse-grained volcanic gravel or the same mixture. Then we will make a mound with the substrate already prepared. We’re going to put the tree on the mound, move it around a bit and make sure the soil is in good contact with the roots.
We choose the planting place well and avoid placing the tree in the center of the pot, since once the operation is done we will not be able to do it again for at least two years. We will tie the tree with the wire that we have prepared and then we will finish the filling.
We will have to introduce it with a sharp bamboo stick to lower the soil, if we do not do it, in addition to avoiding air pockets between the roots, the soil level will drop when watering and we will leave the roots airy.
I hope that with this information you can learn more about when to transplant a bonsai step by step.