Bonsai: root pruning repotting
Quick answer
root pruning repotting for Bonsai: Bonsai roots grow until they fill the container, becoming root-bound and unable to absorb water and nutrients efficiently, eventually killing the tree.
Start here:
- 1. 1. Repot in late winter (February) when the tree is dormant and before the growing season begins
- 2. 2. Remove the tree from its pot, gently brush away all soil from the root system using chopsticks and tweezers
Why root pruning repotting matters for Bonsai
Bonsai roots grow until they fill the container, becoming root-bound and unable to absorb water and nutrients efficiently, eventually killing the tree.
How to handle root pruning repotting on Bonsai
- 1
1. Repot in late winter (February) when the tree is dormant and before the growing season begins
- 2
2. Remove the tree from its pot, gently brush away all soil from the root system using chopsticks and tweezers
- 3
3. Cut away thick roots that point upward, keeping only thin, fibrous roots near the surface
- 4
4. Trim roots conservatively for conifers (preserve root-hairs) but more aggressively for deciduous trees
- 5
5. Place a mesh screen over drainage holes, add a layer of coarse soil at the bottom, then position tree
- 6
6. Fill remaining space with fresh bonsai soil, water deeply, and protect from frost for 2 weeks
- 7
7. After repotting, prune foliage proportionally to compensate for root loss and reduce stress
Keeping Bonsai on track
Repot bonsai during late winter (mid-February) when trees are dormant. Young trees need annual repotting; mature trees every 2-3 years. Never repot conifers right after serious styling or jin-shariki.