Hi If a tree is currently in a pot 30cm (H) x 30cm (W) (18 litres) what increase in size would you go for when repotting? Thanks!
@Mani good evening Mani, the very next size up. It is too easy to pot up in too large a pot, but this should be avoided. Maple roots in pots are happier when they are snug. 20 Litre max.
To me, repotting means pruning the roots, and pruning some of the branches too. I prefer to do it in late winter, early spring, before budbreak.
I should have added that after repotting, a tree should be kept frost-free. Outside as long as it can, but to be brought to a protected place when need be. This may seem evident, but it's better to say it again ;°)
@AlainK I had assumed that would be the case! So, sometimes you might not increase the size of the pot just replenish some of the soil?
A slightly larger pot is the rule for a "patio tree". Using the same pot is what you can do with some bonsai. It's basically the same process, but it depends on what you want to achieve.
@AlainK I had a few more questions! How much of the roots do you take off? Why do you do this? I thought energy is stored in their roots therefore pruning the roots will weaken the tree? Thanks M
@Mani that is always the temptation, but IMO the answer to that Mani is NO. Maples do like their roots snug in pots.