A terrarium can be reminiscent of a specially loved landscape, or planted so that it recalls the lushness of a tropical garden. This kind of miniature garden might also rival the charm of a cactus-studded desert, capture the essence of a ferny wooded dell, or be a midget replica of some other favored outdoor scene. Also, a terrarium can be a Lilliputian dream garden-representing one that is impossible to create under existing indoor growing conditions.

   A glass or plastic container filled with growing plants is called a terrarium. Its size is limited only by display space and plant choice. There are two requisites for terrariums. They need to be transparent and colorless in order to admit light to plants, and waterproof so as to keep moisture from seeping onto the display area.

   Make terrariums in empty fish tanks, rose bowls, brandy snifters, goblets, large drinking glasses, tobacco humidors, glass casseroles, or bottles. Glass jars of all kinds-battery, candy, apothecary, preserve, or pickle-make first-rate containers for under-glass gardens.

   Cover the terrarium opening for humidity-loving plants such as small-growing orchids, saintpaulias (African violets), and the diminutive Sinningia pusilla (miniature gloxinia). Do not use a cover for desert plants such as cacti and other succulents. Have a glazier cut glass or Lucite (a heavy, rigid plastic) to fit large terrariums. Cover smaller bowls with glass plates or clear plastic.

   Making terrariums is one of the most rewarding aspects of my indoor gardening. I have a bottle garden in my study which fascinates visitors, and gives me much pleasure. It is a narrow-mouthed glass jug in which spring water was delivered. It protects a wide-spreading African violet that is always covered with bright blue flowers. Friends cast questioning looks at this terrarium wondering how I managed to squeeze a mammoth African violet into the bottle. The answer is simple: I didn't. I added drainage material and planting soil to the bottle, then sprinkled in some African violet seeds. As the seedlings grew, I used long, slender tongs to pull out the smaller ones. Finally, some five months after planting, I removed all but the strongest one. It began to bloom when seven months old. Today, some five years later, it still blooms steadily.

   Envision the terrain in the garden you are re-creating. Shape the soil into a corresponding landscape, complete with hills, valleys, or plains. A good planting medium for terrariums may be composed by mixing together equal parts of soil, sand, and peat moss. For cacti and other succulents, use equal parts of soil and peat moss with a double portion of sand and Perlite.