Probably the most important part of bonsai care is the watering. How much watering your pant requires will differ from tree to tree. Normally they will need watering often but in small amounts. It usually is good to imitate rain by using a small watering can with a sprinkler attached. This moistens the soil and roots at the same time as cleaning the foliage.
In the winter months plants will need watering less than in the summer months when they need to be watered more frequently, sometimes watering will be required every day. In general you should maintain the soil damp but not saturated and the roots should never be left to stand in water.
Your Bonsai tree will require re-potting approximately once every two to five years depending on the tree you have and how old it is. Younger plants will need re-potting more frequently. As the older trees grow they will use all of the nutrients in the soil and will require to have it replaced. The plant should be replaced in the container in exactly the same position as it was before, the roots however may need to be thinned out and trimmed in order to stop the tree from becoming pot-bound and growing masses of roots which will use up all of the nutrients and moisture at a very fast rate.
It is of utmost importance that you use only special bonsai potting soil or compost.
Bonsai plants can be trained by using special wire to form and shape the branches as they are growing to give you the most aesthetically pleasing shape. This needs to be done in the spring time or early summer months, just after the buds have opened when the foliage is newly formed. It is at this time when the branches are at their softest. The wire remains in place for approximately nine to twelve months.
Pruning is another great part of the art of bonsai growing. For flowering plants the leaf buds should be cut after the plant has flowered and any unnecessary twigs taken off leaving only that which will benefit the shape of the plant.
In the case of pine and other cone bearing trees they need only be pruned when the buds appear in the spring. They should be pruned back to just behind the new growth. This will help avoid excessive growth and will help the branching out process. Trees of the Juniper family will continue to grow throughout the year and so will require pruning more often.