Bonsai Repotting. repot bonsai, repotting bonsai
Repotting Bonsai PDF Print E-mail
Written by Bonsai King   
Friday, 04 July 2008 11:34

Repotting bonsai is essential to maintain good health of your bonsai. It is often advised that you can only repot bonsai when the tree is very healthy. However in some cases you need to repot in order to save the bonsai. As long as you do not damage the fine roots, everything will be ok. When you repot bonsai you must use the wet procedure whenever possible.

Removing the Bonsai from the pot.

Dry procedure

Use a knife or something flat and thin and insert it in between the soil and the side of the pot, do a sawing motion while moving the blade around the edge of the pot. This will separate the soil from the sides of the pot. Remove the wires that anchor the bonsai to the pot. Remove the wire than holds the screen at the bottom drain of the pot. While holding the trunk, push the soil through the drainage hole with your finger or a blunt object. This should lift the bonsai together with the soil. If it doesn't, tilt the pot side ways to get the help of gravity, while holding the trunk and push the soil through the drainage hole. bonsai

Since this is a dry procedure you can not spend too much time combing and arranging the roots because fine roots die when they dry up. If this bonsai has been re-potted several times before, the roots will be easy to comb, spread it radially and cut off the roots that seems to go over the pot. If this is the first time to re-pot, you have to individually isolate each major root by hand, and then arrange it in a radial pattern, use wire if necessary. Do not cut off the roots unless it is pot bound. You can cut of roots shorter in the next re-potting. It takes several re-pottings to gradually shorten the roots to be shorter than the radius of the pot. Be patient.

Clean the pot, put a new screen at the bottom hole, wire it, put wire to anchor bonsai, put a gravel layer, mix soil, put mound on center, place bonsai on mound, press down with twisting motion, wire the bonsai, put the rest of the soil, use stick to guarantee no air space, water while tapping the surface of the soil, put additional soil on parts that collapsed or sank down during watering., then water again until no part of the soil collapses anymore, put you final topping.

When to repot bonsai?

1. Repot bonsai when you start seeing a lot of ants crawling all over your bonsai.

2. Repot when the bonsai is root bound.

3. Repot bonsai when it takes time for water to drain.

When repotting:

1. The soil level must be below the rim of the pot.

2. Bare root whenever possible

3. Prune roots only when the plant is healthy.

It is often advised to prune the foliage when you prune the roots. I do not advise this. When you prune you create a lot of open wounds on your bonsai. You will notice that no growth occurs for a time until the wounds heal. When a plant is wounded it needs energy to form callus. If there are too many wounds and not enough stored energy within the plant, the bonsai may die or a few branches could dieback. The trunk, branches, foliage, and roots all store food for the plant. When you traumatize the roots by pruning, it needs all the energy it could get from the rest of the plant. If you reduce foliage, not only will you throw away the energy stored in the foliage but also, the wounds would be so many and will require more time and energy to heal.

The reason that it is advised to prune the top as well is because of the water requirements of the bonsai. If there are fewer roots, not enough water can be supplied to the top of the plant. The water evaporating through the leaves will be more than the roots can supply. This is also one reason why it is advised not to expose it to sunlight as the leaves evaporates water to cool the plant. This condition however is only for a short time, the plant will go back its former glory when the fine roots come back in a few days.

The best solution is to keep the plant in a high humidity environment during healing. The high humidity will reduce or stop evaporation completely while giving the plant enough time to heal and grow new roots. This is accomplished by constructing a small green house or enclosing the plant inside a plastic bag for a few days.

Wet Procedure 1

Removing the bonsai from the pot using pot submergence method.

I do this when I need to bare root the bonsai.

Remove wires that anchor the bonsai and the drainage screen. Then, get a container bigger and deeper than your bonsai pot. Put the bonsai and its pot in the container. Fill with water up to the rim of the pot. Wait for the pot to absorb the water. Then continue adding water to maintain the level at the rim of the pot. Let it stay in the container for 15 minutes or until you can feel that the soil has softened enough. Now hold the trunk and do a gentle up and down movement. Continue doing this until the root ball goes off the pot. Put the bonsai aside and remove the pot to create more space. Get the bonsai and move it up and down gently at first. When most of the root ball has mixed with the water you can start vigorously shaking it until all the soil in the root ball is gone. At this stage, you will see a lot of insects, worms, bugs, and larvae floating around, be brave. If the water has become too muddy, replace it with clean water.

The whole point of the wet procedure is to minimize excessive damage to the roots, see its health condition, and eliminate infestations. In the dry procedure you could hear roots snapping as you remove the ball out of the pot, and as the root ball crumbles apart.

From here, it is a lot easier to fix the roots. While arranging the roots, submerge the roots from time to time in water to maintain moisture. Then follow the dry procedure in returning the bonsai to its pot.

Wet procedure 2

Removing the bonsai from the pot using water hose

Remove wires that anchor the bonsai and the drainage screen. If the soil is compacted you can immerse the whole pot in a basin for 15 minutes to soften the soil. Tilt the pot about 45 degrees. Using a water house gradually erode the soil from the top of the pot. Continue hosing the pot until the pot is empty of soil. To hasten the process you can tilt the pot 90 degrees. Then arrange the roots and re-plant the bonsai as discussed above.

Bonsai Repotting Video


Last Updated on Monday, 05 April 2010 17:11