Bonsai trees, though miniature, are hardy and can provide many years of enjoyment. They are pruned to maintain their small size. Growing bonsai trees indoors is similar to growing other houseplants, but they do require some additional attention.
Plant your bonsai in a small to medium-sized container. The tree must remain in its original container until it matures, so make sure you leave ample space for growth. The maturity period will depend on the type of tree you have. For most trees, maturity is reached within the first 24 months. Speak with your local nursery or horticultural specialist for assistance in determining the accurate time frame.
Water your bonsai tree regularly. Watering schedules vary depending on the tree, so pay close attention to the tree's moisture levels. Do not water the tree until the soil begins to feel dry. This will help you avoid overwatering, which promotes disease and may damage or kill the tree.
Make sure the soil provides the nutrients the tree requires. Use quality soil that feeds the tree and promotes level pH balances. The soil should be somewhat sandy and provide ample drainage. Complement your soil with fertilizing, ideally in early spring and late fall. The fertilizer should include equal amounts of phosphorus, potassium and nitrogen. Nitrogen levels must remain relatively low to prevent root burning.
Place your bonsai tree where it will receive at least six hours of direct sunlight each day. Bonsai trees require a combination of direct sunlight and water to create nutrients, other than what is provided in the soil. Lack of sunlight may cause the tree's foliage to wilt and promote root rot. Keep the room moderately warm (70 to 75 degrees F) and moderately humid.
Prune your tree regularly. The bonsai tree requires pruning of its roots, branches and stems to maintain its small size. Prune its new growth to promote more vigorous growth. Never prune all of the tree's new growth simultaneously, however.
Use thin, pliable wires to wrap around the branches to shape your tree. Wires are optional but when used, they should be left on the tree for at least six months. Cut the wires from the branches--never unravel them. Unraveling may damage the branches.