All Bonsai will need to be re potted at least once every couple of years. Bonsai that are in small or shallow pots should be re potted every year.
The plants you grow as Bonsai will be either Deciduous (lose their leaves in Winter ) or Evergreen (hold their foliage all year around) . Depending on what category they fall into will depend on the time of the year they are best re potted. To see which is the best time to re pot each tree you have please refer to our re potting guide.
The reason we repot Bonsai every year or two is so the plant doesn't become pot bound.
We take the plant out of the pot and tease out the root system with a tool called a rake. Then we trim up to 1/3 of the root system straight across the bottom and the sides with a root pruner. Make sure the 2/3 of the root system that remains does not have the soil shaken out.
Cut some gauze and place it over the drainage holes and secure it in the base of the pot with a small piece of wire. By securing the gauze it won't shift around whilst you conduct the process of re potting your Bonsai. The gauze will allow the water to drain out but keep the potting mix in the container.
Trees planted in shallow pots, tall trees or cascading trees should be held into the pot with some low gage wire. This is simply done by pushing the two ends of a piece of wire up through the drainage hole bringing them up to the top of the root system and then pulling them tight and twisting the two ends as they meet up again near the centre of your tree. Cut off any excess wire.
However before you tie in your Bonsai you should fill up the Bonsai pot about 1/3 of the way up with fresh Bonsai potting mix containing some slow release fertiliser. Position your tree in the pot slightly off centre and make sure the base of the trunk sits above the rim of the pot. Then tie your Bonsai in with the tie wire that was inserted from the drainage hole before. Once secured place more potting mix over the top of the root ball and on the sides.
Get plenty of the new potting mix intergraded with the root system as possible by pushing in with a chop stick. Once you feel that the potting mix is firm and there are no huge air pockets finish off by tamping down the surface with the flat end of your rake or a spatula. Be sure to leave a gap of 1cm from the top edge of your pot so when you water your Bonsai it doesn't roll over the top of the pot.
After re potting it is a very good idea to give your Bonsai some Seasol. This will stimulate the root system and get it actively producing new feeder roots into the potting mix very quickly. Mix with water according to the rate on the bottle and either water into your Bonsai via a watering can or dunk your Bonsai in a container or tub of it. You can repeat this every two weeks for the next month after re potting to help re establish your Bonsai to strong vigour.