This is the start of the re-potting season for me, March and April depending on the weather.
I will be watching for those bright and windy days when the bonsai could dry out. If the tree starts to wake up and grow and the pot is bone dry it will die!
As soon as I see the buds on deciduous trees starting to swell it is time to re-pot.
I like to take my time with each tree, look at it's health and the root structure. While re-potting I will ensure the roots are well spread and any rotten ones are removed.
This year I will be using Akadama as the main ingredient of my soil. Previous years I have used John Innes but have found this not to drain as well and I feel the trees did not reach their full potential.
While the deciduous trees are without leaves it's a good time to look at the branch structure. Re-wire those that need changes, prune out any dead wood or branches that do not fit the desired style.