Bonsai repotting

The first planting in the container

 

Transplanting for the first time from a large pot or soil into a container may seem not so difficult at first glance, but we are dealing with a miniature plant, where every small detail is crucial. Before starting the transplanting, we need to choose the appropriate container and know how much root trimming will be required to ensure the sapling fits perfectly in the container as we planned. Very often, during the first transplanting, things don’t go exactly as planned. It may not be possible to trim enough roots for proper placement in the container, or you may realize that creating a beautiful bonsai requires significant adjustments to the plant’s shape and size. You must be prepared for all of this and try to find an optimal solution to the situation.
To begin the transplanting, prepare the appropriate container, the required amount of soil, tools, and necessary materials. First, to prevent the soil from being washed away during watering, the drainage holes of the container should be covered with a fine metal or plastic mesh. To prevent the mesh from shifting when filling the container with soil, it should be secured with wire.

 

After transplanting, until the plant has properly rooted, it is essential for the bonsai to be securely fixed in the container. To do this, insert wire from the drainage holes at the bottom, through which we will secure the newly transplanted plant. This wire is only temporary, and once the plant has firmly rooted, it should be removed. If there is only one drainage hole, or if you think you won’t be able to pass the wire through the drainage holes into the necessary position, it is better to make additional small holes in the container for fixing the wire. After this, place a layer of small gravel, about 1-1.5 cm in height, at the bottom of the container to improve drainage, and only then add the first layer of soil.

The next step: choose the location in the container where the plant should be placed. In rectangular and oval containers, the plant is positioned at the intersection point of 1/3 of the container's length and 1/2 of its width. In the SHAKAN style, the tilt should be directed towards 2/3 of the container's side. In the CHOKAN and MOYOGI styles, the longest lower branch should be positioned above 2/3 of the container's length.

In round, multi-sided, and square containers, the plant is placed in the center. The bonsai is also positioned in the center in tall containers, as well as in HAN-KENGAI and KENGAI styles.
When planning to repot, it is important to consider the moisture level of the soil in which the plant is currently planted. It is bad when the soil is too wet. In such cases, it is quite difficult to remove excess soil from the roots. Therefore, try not to water the plant a few days before repotting. Repotting typically happens during a resting period, and the plant will not be harmed if it is not watered for a few days.

How to remove the plant from a large container: First, cut off the roots that are protruding from the soil ball. Then, begin removing the soil. For this, use a rake and a pointed stick. Gently insert the pointed stick into the soil in several places from the top. This will loosen the soil gradually, allowing you to remove the soil from the roots more easily.

Carefully determine the size of the soil and root ball that should be kept for the plant to fit into the container you've selected. Ensure that after removing excess soil and trimming the roots, there is enough space in the container for new soil. This may not work on the first attempt. Therefore, once you've removed a certain amount of soil and roots, place the plant in the container, observe, and determine how much more soil and roots need to be removed for the plant to fit perfectly into the container as planned. You may need several attempts to achieve this.

Removing the soil is done very carefully. The fine roots, which provide the plant with nutrients, are easily damaged. Although a certain amount of roots must be trimmed before planting in the container, carelessness and haste can damage even the roots that are necessary for the future bonsai. After removing the soil, we shorten the remaining roots so that only a few millimeters of the root ball stick out. Use well-sharpened pruning scissors for trimming thick roots, as the cut must be smooth. Always cut off any damaged roots. Thick roots should be cut in a way that the cut side faces downward. New fine roots will grow better from the cut site. Once the required number of roots is trimmed, we begin placing the plant in the container. In the place where the plant should be placed, create a small mound of soil. Place the plant on top and gently press it down in a semi-circular motion to ensure the raised soil is evenly distributed under the roots. Then, we thread the wire through the holes in the container, wrap it around the plant’s trunk or a large root, and firmly secure it in place.

Attention should also be paid to the depth of planting in the container. The plant should not be planted too deeply, nor should it be planted in such a way that the surface roots remain significantly above the container's edge.

 

Then we begin filling the remaining space in the container with soil. To ensure that no gaps remain beneath the root ball, it is necessary to carefully tamp the soil around the root ball with a pointed stick. This is important to prevent any air pockets between the roots, which could lead to the deterioration of some of the roots later on.

 

For various reasons, it becomes necessary to completely free the roots from the soil during transplanting. To make it easier to remove the soil, the roots can be rinsed with a stream of water. Preparing the container (gravel, mesh for drainage holes, wire to secure the mesh, and the first layer of soil) is done similarly to a plant with an intact root ball. After trimming the roots to the desired size, carefully untangle the intertwined roots, spread them out in all directions, and place them in the container at the appropriate location. Secure the plant with wire and fill the container with soil. Once the container is completely filled, take a pointed stick and gently, slowly, tamp the soil over and around the roots.

For coniferous plants, removing all the soil from the roots and rinsing with water is generally not done, as it may cause the plant to dry out. Once everything is finished, the plant should be watered. To do this, place the plant in a larger and deeper container than the original one and pour enough water so that the surface of the container is covered. Air bubbles will begin to rise to the surface of the water. After 2-3 minutes, the bubble rise will stop. This indicates that the soil in the container is completely soaked. Remove the plant from the water and place it in a location protected from wind and sunlight. Never compact the soil after watering.

 

If the newly transplanted plant is quite large and heavy, take a watering can from which the water flows in a fine stream and water the plant generously. When transplanting, pay close attention to trimming the roots. It is very important to maintain a balance between the number of roots and the growth. Do not reduce the number of roots just because the plant does not fit into the container you have chosen. Over-trimming the roots can prevent the plant from receiving sufficient nutrients.

   Special care is required when transplanting coniferous plants. Compared to deciduous plants, conifers are more sensitive to excessive root trimming. It is generally accepted that only one-third of the roots should be trimmed when transplanting a coniferous plant. However, this is not a strict rule that cannot be broken. An experienced specialist can tell by sight how much root trimming is appropriate for a particular situation. If a large amount of roots must be trimmed, try to proportionally reduce the size of the plant as well. The plant can either be transplanted once it has already formed, or we can transplant a sapling and, after it has properly rooted and stabilized, begin its shaping process.

Transplanting from one container to another

   At a certain point, it becomes necessary to replant the bonsai. This need arises from several factors:

• The soil has been depleted and no longer contains enough nutrients;
• The plant's roots have grown to such an extent that there is no longer enough space for their development;
• The bonsai has grown, and its shape and dimensions no longer fit the size of the container.

 

 

In the first two cases, if the size of the plant allows, the bonsai can be re-planted in the same container after pruning the roots and replacing the soil. The period when re-potting becomes necessary varies for each plant. Pine tree roots grow slower than those of deciduous trees. Their re-potting happens every 3-5 years. Some deciduous plants' roots fill the container so quickly that re-potting is required every year. In general, young trees (under 10 years old) need re-potting more frequently than older plants.

If you notice that the bonsai has grown to the point where the container size is no longer proportional to the plant, then you need to choose a larger container and transplant the bonsai into it. In this case as well, the timing for changing the container depends on the plant's growth characteristics. The procedure for transplanting from one container to another is the same as when the plant is first placed in a container.

 Time to repot

Transplanting of plants is done in late autumn or early spring, during the dormant period. If you transplant the bonsai in late autumn, the main concern will be protecting the plant from winter frost and wind. If you transplant it in early spring, make sure to keep it out of direct sunlight for a period of time. One week after the buds begin to grow, take the bonsai outside for a short time (1 hour) in the sun. After that, gradually increase the time it spends in the sun each day. After a month, you can place it in its permanent location.
Most species of coniferous plants are transplanted in early spring, when new buds begin to develop.

Moss

After transplanting, it is essential to take care of the surface of the soil in the container. The surface should be leveled and cleaned. Some specialists try to cover the surface with a decorative layer. They use finely crushed stones or marble for this. However, in my opinion, the most suitable surface for bonsai is one covered with moss. Moss looks quite attractive and natural in the container and does not hinder the water from reaching the soil when watering. At the same time, it helps maintain moisture and prevents soil erosion from the surface, both during watering and on rainy days.
Since the soil in the container is constantly (more or less) wet, the surface often naturally gets covered with moss. However, it is also possible to "artificially" cover the surface with moss. You can find moss in damp and shaded areas: it grows on building walls, stones, or asphalt. Carefully remove the moss with a knife and remove as much excess soil as possible. Just before use, place the collected moss in a container and add water. Wet moss is easier to apply to the surface. Gently arrange small pieces of moss around the plant, placing them close together with no gaps, and press them down lightly. Under no circumstances should you cover the surface roots with moss.

Also, the collected moss can be dried in the shade for 2-3 weeks. Crush it finely, mix it with a small amount of soil, and sprinkle it in a thin layer over the surface of the soil. With regular watering, the moss will "revive" within 1-2 weeks.