Repotting your tree is one of the most important maintenance steps in the overall care of your bonsai. Luckily the process for repotting is fairly simple and straightforward. To view a tutorial on how to repot your tree, click here. However, one of the most common pitfalls that can lead to an early tree death is also one of the easiest to overlook.
Air pockets occur when you add soil mix to the pot around the tree and forget to add soil underneath the roots of the tree. This is where a repotting stick is very useful. While repotting, make sure to poke around the bottom of your tree at an angle to see if soil continues to fall underneath the roots of the tree. Wiggle the repotting stick. If you don't feel a good amount of pressure against the stick, there's a good chance that an air pocket exists right underneath the roots. If left unfixed, the air pocket will dry out that portion of the roots and lead to your bonsai dying. This simple extra step will lead to a higher success rate when repotting.
Another tip is to create a mound of soil prior to placing the tree in the new pot. This way, when you place the tree in the new pot, you'll push against the mound which will keep air pockets from forming as you position the tree.
Air pockets occur when you add soil mix to the pot around the tree and forget to add soil underneath the roots of the tree."
This is another very common mistake and happens very often with beginners new to the hobby. Fertilizer is great for maintaining the overall health of an established tree. However, when repotting a bonsai into a new pot and cutting roots, the tree will undergo some stress. Excessive fertilizer will force the tree to push quicker than the tree can establish itself in the new pot. The safest method for using fertilizer is to let the tree establish itself for a few weeks. After the tree is no longer stressed, fertilizer can be added to give the tree some nutrients.
The overall goal is to put the least amount of stress on the tree. Fertilizer works great on a stable and established tree.
The overall goal is to put the least amount of stress on the tree. "