Re-Potting Your Bonsai
Re-Potting Your Bonsai
You will generally need to prune and re-pot you bonsai tree every few years. Bonsais need to be re-potted to prevent them from becoming root-bound and to facilitate the development of new feeder roots which will allow for more efficient moisture absorption for the tree. You should also switch out the old soil for new soil because it is most likely stale and will only hinder the plant’s growth.
You can easily determine if it is time for a bigger pot, if you notice the roots are crowding in the sides or the water is taking much longer to drain. To begin, you will need to carefully and gently lift the tree freeing it from its current pot–tilt the pot to one side and move the plant by the trunk’s base. Do not tug hard on the trunk, if the plant does not free itself immediately, you might want to tap the side of pot with your hand in an effort to loosen the plant’s root ball, another method is to push something up through the drainage openings and slowly push the plant out.
Once the plant is free from the pot slowly separate any accent plants and moss (you can use a knitting needle, chopstick, metal hook or something similar) you will then want to untangle the roots and gentle brush out the old soil. You should always start at the ends and work around the plant. Do not tug or pull at the roots, you really want to comb because if you are not careful you could tear or damage an important root.
Keep brushing off and shaking off excess soil (until the ball is about a third or a half of its original size).
At this point, it is a very smart idea to spray down the roots with water, because you do not want them drying out and you do really want them to be as clean as possible when you start to prune them. You should always use the sharpest possible cutters to prune the plants roots. You can find pruning scissors created just for bonsai root trimming on the market, but you can just use your normal set of bonsai clippers.
The biggest reason why you want to get rid of as much soil as possible is because the soil will dull the blades, the less soil on the roots, the sharper your blades will stay throughout the process.
You should begin by cutting away the thicker, older brown roots which tend to congregate towards the outer edge around the pot’s edge, and these roots can stop or restrict the development of younger feeder roots. You should prune away about a third and up to a half of these roots but you will need to be careful that you do not accidentally cut away too many feeder roots.
Now, turn your attention to the thin roots that hang down into the pot and trim them to better suit the new pot’s shape. The roots should be shaped to fit easily into the new pot with about a 1 to 2 cm (.5 to .75 inch) gap between them and the edge.
You have now completed the most demanding aspect of re-potting (if you think you have accidentally cut too many feeder roots, do not panic as they will regrow from where they were cut).
You can now either cleanse the pot it was originally in or find a new pot that is better suited for the tree–be sure to place a wire mesh to cover drainage holes so the soil does not leak out. When you place the plant into the new pot, please be aware that it is now quite unstable and you will have to add some anchors to keep your tree from tipping over.
Just run some wire up into the holes or through the anchoring holes and leave them until you need to secure them. You do not need wire that is particularly thick. Put a thin layer of gravel over the wire mess (this will help drainage) and then add the soil. Figure out how the plant needs to be best situated (most of the time it needs to be off-center and towards the rear of the pot) then create a small mound of soil for the plant to perch on. Next, place the bonsai on its prepared mound and gently nestle it in and spread out hte roots so they are even over the soil.
If you are content with the position and height of the plant (keep in mind it will be set there for at least a year), you will then need to take the wires you had fixed earlier and twist them together with a pair of pliers above the main root ball–make sure it is being held securely and will not tip. You can remove the unsightly wires after a few months or whenever the tree has settled into the new pot and is stable.
You will now want to add enough soil to reach the bottom of the trunk or just below the lip of the pot. Tap the pot’s sides with your hand and confirm that its soil is settled and you cannot see any gaps where the roots are. Take a chopstick (or like device) and ensure that the roots look correct in the soil and are place in the correct manner.
With the soil in place you can add the other features to your bonsai like: rocks, accent paths, moss, or gravel (or any other plant or decoration to better enhance your vision). If you are replanting moss you will need to get rid of the old soil by cutting it off prior to you planting it and try not to plant a moss plant that is too big for your tree.
It is now time to give our tree a thorough watering (the water may cause the soil level to drop further and you may need to add more). now put your tree in a place where it is in moderate temperatures and not in direct sun, it will need to recuperate. You should not add fertilizer as it can stress the plant out or burn it. In a month, you can give it some fertilizer to the plant as the roots have most likely recovered from the ordeal by then.
You will also need to prune the branches to balance the pruning you have just done on the roots–it will not place the plant at a further disadvantage and the plant should recover in a timely fashion. Branches and roots usually grow at the same rate.