There are several reasons for repotting:

impoverishment of the soil: over time the nutrients of the earth are depleted; root growth: with the growth of the roots the bonsai tends to rise from the ground or rather cause the bread of earth to rise while the grown capillaries can create a block in the drainage of the pot or come out of the pot holes; bad drainage: that is, no water can be seen coming out of the pot holes; the soil too compact: the case of clayey soil such as that of export bonsai, this type of soil, excellent for retaining moisture , it has the defect but once dried it becomes almost water-repellent, that is, water has a hard time penetrating it. When repotting Bonsai repotting does not follow the general rules valid for common ornamental plants. vegetative, generally the optimal periods are spring and autumn depending on whether they are outdoor plants (Maples, Oaks, Elms, etc.) that vegetate in p spring, repotting should be done in winter, if the species of bonsay are outdoor plants (Maples, Oaks, Elms etc.) which vegetate in spring, on the other hand, being tropical genera that vegetate in summer, repot in spring. rest period the traumatic effect of repotting on a tree is reduced to a minimum precisely because the tree does not yet have to maintain a mature vegetation.Generally a bonsai should be repotted every two years, but this frequency is purely indicative and influenced by various factors, such as let and species of bonsai, it is in fact necessary to distinguish between young plants that vegetate faster and need to be repotted every year such as Ficus, Elms, Hornbeams etc., from older plants that vegetate more slowly are repotted every three or four years, examples are pines, junipers and evergreens in general.

To start the repotting operation you need to prepare the vase, but first of all, choose it, the choice of the most suitable vase both in size and in the style of fundamental importance for the composition as a whole.

And certainly a choice conditioned by many botanical and aesthetic factors depends on whether you want to grow the bonsai, you need to replace a pot with a larger one but always rather low to avoid the growth of roots downwards, in the case instead the bonsai already of the desired size and maintains the right proportion pot plant, either the original pot is used or it is replaced with one of the same size. Once the pot has been chosen, it is necessary to sterilize germs and parasites, make holes for drainage if there are no and attach a net to them with a copper wire, the meshes of the net must be thin to allow the excess water to flow out, prepare the bottom with akadama draining material, pumice lapillus etc. and add a layer of soil before going to place the bonsai Performing repotting At the time of repotting it is advisable to choose a place in the shade and sheltered from the wind and always keep a nebulizer for the roots at hand in case there was need. bonsai from one container to another it is advisable to work with dry soil, this is because it makes it easier to separate the plant from the old container and to arrange the roots more easily in the ground.To remove the bonsai from the old container you should never take it by the trunk because they would get lost many root hairs, it is recommended to proceed to extract it by overturning the pot and gently beating the bottom to let the plant out, in case it struggles to come out you can provide with a blunt stick by pressing from the drainage holes. the roots from the old earth, always with the help of a stick you gently look for d i freeing the roots from the ground this is an operation that requires time and patience, if the roots are rebellious or too long they must be reduced by a third of their length, the broken or dead roots must also be eliminated, if the taproot is popped the main root of the entire root system.After pruning, we proceed to place the bonsai in the pot where a layer of soil has already been laid, we always proceed with the help of a stick to spread the roots in the first layer of soil and, once checked the right position of the bonsai, add more earth without filling the container to the brim, press it gently with the stick to avoid pockets of air harmful to the root system. by immersion in the water of the vase itself up to the brim and is placed for twenty days in a shaded environment and sheltered from the wind. fertilizer is given only a couple of months after repotting.