Repotting your Bonsai
Repotting is carried out to prevent your plant becoming root bound and starving to death. It helps maintain your tree in a small pot but does not reduce the size of your tree. Apart from watering, it is probably one of the most important and misunderstood processes in Bonsai
Early Spring is the best time to carry out this process.
Select the tree to be repotted. Prepare all the items you will require: Tools, soil, clean water, mesh, gravel or cover stones. These should be on hand as the process should be carried out as quickly as possible to prevent the roots drying out any more than is necessary
This tree has not been repotted for two years now and it is starting to yellow and loose vigor.
The root ball has become a solid mass and lifts from the pot with relative ease. If the lip of your pot cuts inwards you may have to run a knife around the edge. Remove any pieces of mesh that were not wired to the pot and have become embeded in the roots. You can see new healthy roots by the mesh on this plant that is a good sign and indicates an appropriate time for repotting. Take this opportunity to check for rot from wet areas or bugs, such as mealy bug which can infest the roots of a stressed plant. Rot could be a sign that the drainage of your pot is not right look for pockets where water may sit, or blocked or undersized holes.
Remove about one third of the root mass from around the outside and bottom of the ball. To do this you can use a root hook. If you have no hook you can use a fork with a tine bent at right angle to the handle to make a hook. If you think bending one of the forks might cause a little house hold strife a chopstick or pencil would do just as well.
Trim any damaged or excess roots with a sharp pair of scissors. Don’t use your good pruning scissors you will be cutting through dirt and the odd stone. Make sure all your tools are kept sharp and clean.
Take the opportunity to clean your pot remove any old soil and green colour from the outside.
Replace the mesh over the holes. It is a good idea to wire the mesh in as shown. This will prevent it moving when you replace the soil or as the roots grow around it. The mesh will prevent the soil falling out and the bugs climbing in.
Place a layer of soil in the bottom of your pot and reposition you plant. You can see from this picture how much root and soil has been removed.
Replace the removed soil with fresh bonsai soil. You may need to make sure the soil is down around the bottom edges of the pot, a chopstick is useful for this.
Replace the top stones these help retain moisture prevent weeds and look good too. Some of the stones on the top of trees from garden shops are glued or mixed with glue before they are placed, this is not good and is only done to stop people knocking them off in transit. If you come across this in a bonsai, remove them as soon as possible.
Trim your tree to remove any excess growth. Repotting is a good time to thin your plants foliage mass to help reduce the stress on the bonsai. Water thoroughly, if you can it is a good idea to immerse your tree in water, leave it there until the bubbles stop comming out of the soil. Take it out and place your plant in a sheltered position with a little shade for a few days.