Indoor blooms can brighten a winter household

Reluctance to see another gardening year end is almost offset by the pleasurable sense of being snug indoors against the returning cold. And to help with the transition, there are the plants overwintering indoors - the lantanas, fuchsia, geraniums, or begonias we've potted up and brought inside. Like the houseplants that have summered outdoors, they are in lush good health and will benefit from a regular misting in the home's drier atmosphere.

This change in gardening season is also an excellent time to try a few tropical bulbs for bloom in the house this winter. Some, like callas and caladiums, are inexpensive, extremely handsome, and easy to grow. They make wonderful presents.

The stunning calla lily (Zantedeschia) carries its funnel-shaped spathes on erect stalks and enjoys a temperature in the mid-60s at night, the mid-70s during the day. The hardiest is the white Z. aethiopica, which grows year-round without a dormant period, reaching 24 inches and blooming several times a year.

This handsome plant is grown from one tuber planted about an inch deep in an eight-inch pot. Autumn is an excellent time to start the tubers. Grow them in bright light and water sparingly until the foliage develops, then move the plant into the sun to bloom, increasing the amount of water and adding a liquid fertilizer.

There are also yellow and pink callas that are slightly smaller in size and need to rest for a two- to three-month dormant period each year.

Z. elliottiana is the gold yellow calla, with leaves spotted white, and should be grown one tuber to a five-inch pot. The pink Z. rehmanni, blooming on one-foot stems, is quite beautiful. Its leaves are a solid dark green. The tubers of both these callas should be rested after flowering. They can be brought back into growth by repotting the tubers in fresh soil.

The other inexpensive but colorful bulb to grow indoors in winter is the caladium, native to the humid Amazon basin and an easy houseplant if grown in the bright indirect light of a north or east window. It prefers daytime temperatures in the 70s, and a night temperature in the low 60s. Caladiums come in wonderful colors. Tubers can be planted one to a six-inch pot or three to a 12-inch pot, and top-quality tubers cost no more than $2.50.

Caladiums begin to make a good display two months after planting, becoming fully mature at three months and giving several months of very colorful pleasure after that. A period of dormancy sets in about the seventh month. At this point, begin gradually to cut down on water until the foliage has died back completely. Store the tubers in a cool, dry place for four or five months before starting them into growth again.

A houseplant that provides years of trouble-free growth and bloom is the Clivia miniata, a handsome pot specimen with evergreen leaves that begins to bloom annually only when it is thoroughly pot-bound.

Once at home in Victorian parlors, clivias are finding new popularity because of their good looks and easy culture. While they tolerate sun, they prefer the light shade of a north or west window and a temperature not much below 65 degrees F. - which makes them good candidates for warm city apartments.

Clivias bloom in early spring, sending up a remarkable shaft carrying an umbel of large, orange, lily-shaped flowers. The flower stalks increase in number as the plant matures and as long as the roots are left undisturbed. Withhold fertilizer after the blooming period, then begin feeding again during the next growth season.

You will probably find some young clivias in the hothouse of a favorite nursery for about $12 or $15. One of the major United States bulb dealers offers a five-year-old, blooming-size clivia potted in a terra cotta pot with saucer for $33 - not a bad price for a lifetime plant that astounds you with its bloom once a year!