Indoor bonsai

Indoor bonsai are bonsai which are cultivated for the indoor environment. Traditionally, bonsai are temperate climate trees grown outdoors in containers. Kept in the artificial environment of a home, these trees weaken and die. But a number of tropical and sub-tropical tree species will survive and grow indoors. Some of these are suited to bonsai aesthetics and can be shaped much as traditional outdoor bonsai are.

Note that bonsai and similar practices like penjing, hòn non bộ, and saikei all involve the long-term cultivation of small trees in containers. The term bonsai is generally used in English as an umbrella term for all miniature trees in containers or pots. In this article bonsai should be understood to include any container-grown tree that is raised indoors and regularly styled or shaped, not just one being maintained in the Japanese bonsai tradition.

The largest difference between indoor and traditional bonsai is, of course, the enjoyment of an attractive, fully leaved plant in winter instead of a dormant, leafless tree. Other differences include the faster growth rate of tropical plants, which accelerate all steps of the bonsai evolution. Moss covering, a common soil covering for outdoor bonsai, will not survive indoor conditions.

Compared to the usual potted house plant, bonsai are rooted in a much smaller amount of soil. Consequently, they require more frequent watering and feeding. This form is therefore best suited for drought-resistant species. Compared to usual house gardening, bonsais require a lot more pruning, both of branches and roots. This often requires a significant shift in attitude for house gardeners.

The spiritual benefits of bonsai cultivation (bonsai no kokoro) are available equally to classical and indoor bonsai gardeners

Many of the techniques used to grow and shape outdoor bonsai apply equally to indoor bonsai. For example, shaping techniques like pruning, wiring, and grafting work much the same for both types of bonsai. But indoor bonsai also have some special requirements for cultivation and care.

An indoor room comfortably lit for human use provides too little light for most species of tree to grow. Few species will thrive with less than 500 lux available several hours per day. Successful indoor bonsai cultivation requires either selecting from the short list of low-light-tolerant trees, or providing additional lighting for the trees. Insufficient light may not kill some species outright, but will make their growth so slow that the bonsai shaping techniques cannot be used: the plant will not grow back after pruning or leaf trimming.

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Wikipedia