Some devoted indoor gardeners might like to expand their horizons by training some of their plants as bonsai.

The art of growing plants in this form originated in China and, in the 14th century, was introduced to Japan where it reached its peak of perfection.

Japanese bonsai are in no sense house plants; however the indoor gardener can create bonsai using familiar house plants.

Art and horticulture combine in creation of bonsai - dwarfed, potted trees and shrubs. The art is in observing certain aesthetic rules for training plants, while directing horticultural knowledge to the needs of the plants. The word bonsai (pronounced bonesigh) means "tray planting." The pot or tray is a ceramic container with small "feet" and a drainage hole. The plants may be one or several small trees or shrubs. The aim is to grow a miniature tree that has all-the elements of a large tree growing in a natural sefting.

In introducing the Brooklyn Botanic Garden handbook, "Bonsai for Indoors," the editor writes: "Bonsai in Japan evolved slowly over many centuries and the plants selected were the best possible ones - for Japanese growing conditions and climate. The art did not have its origins in hot, dry, sometimes poorly lit apartments - the only condition that many Americans provide for plants. . ." The trees so loved by the Japanese usually withered and died in American homes.

Then a few innovative American gardeners began to experiment with house plants. Tropical and subtropical plants have been grown as house plants for years but not in the Japanese manner as bonsai. American gardeners have applied aesthetic rules of bonsai to create expressions of American culture as the Japanese creations express aspects of their culture today, interest in growing bonsai, both outdoor and indoor plants, is widespread in the United States.

By combining traditional procedures for handling house plants with bonsai concepts, growers have created different and freer bonsai styles.

Bonsai are kept small by a combination of top and root pruning and growing in small containers. New growth is trained by refined techniques of wiring. Not all plants are equally effective but many with which indoor gardeners are familiar and which they have successfully grown as houseplants are suitable and are readily trained. Each gardener should select plants that grow best in his home. Examples are: Citrus species such as calamondin orange; mistletoe fig (Ficus diversifolia); dwarf pomegranate (Punica granatum nana); sea grape (Coccoloba uvifera); and Pittosporum tobira. Although any plant that is pleasing to the eye can be dwarfed, varieties with small foliage, flowers and fruit are preferable to maintain the scale of the dwarfed tree.

An increasing amount of literature is available on selection of plants and training them according to bonsai rules. Especially useful for indoor gardeners is "Bonsai for Indoors," Brooklyn Botanic Garden Handbook, 1976; address, 1000 Washington Ave., Brooklyn, N.Y. 11225; $1.75 postpaid.

Other sources of information are: Bonsai Clubs International, Horace Hinds Jr., executive secretary, 445 Blake St., Menlo Park, Ca. 94025; the American Bonsai Society, Lynn Perry Alstadt, executive secretary, 228 Rosemont Ave., Pa. 16505; and, locally the Potomac Bonsai Association, Col. John W. Hinds, 1611 Taylor Ave., Oxon Hill, Md. 20022.

The beauty of a house plant depends on the care you give it. Adequate care depends on your learning what is proper care for the plants you have. Here are some basic rules to observe.

1. Avoid over-watering. There is no time schedule to be followed. Some plants do best if the soil is kept moist; others do best if soil is allowed to dry moderately between waterings. It's up to you to know which is which. When in doubt, don't water.

2. When you do water, soak the soil throughly. Don't use ice-cold water, especially on tropical plants. Don't let the pot stand in water.

3. Do not fertilize resting or dormant plants.

4. Never feed an ailing plant.

5. Increase humidity by grouping plants or by setting the pots above a tray of gravel, sand or peatmoss which is kept wet.

6. Avoid sudden temperature changes and drafts. Keep plants out of cold or hot air blasts. A satisfactory temperature range for most plants is 65-70 degrees in the daytime and 55-60 degrees at night.

7. Supplement natural light with artificial light if plants are placed in a dark location.

8. Isolate new plants for several weeks until you are sure they are not bringing in unwanted insect pests.

9. Examine your plants periodically to prevent build-up of pest populations.

10. Use natural methods of controlling pests, such as syringing or washing plants and hand-picking insects.

11. Handle insecticides with care. Follow directions on containers. Be sure you know why you are spraying. Not all aerosol insect sprays are suited for use on house plants.

12. Remove dust or other deposits from upper and lower leaf surfaces by wiping leaves with a soft moist cloth.

Jane Steffey is on vacation. One of her more popular columns is being reprinted this week.