With fluorescent stand, you can put a lettuce patch in the dining room

Growing vegetables indoors under lights is a nice stunt but not very practical unless you have the space and a good-size wallet. Lettuce, however, is an exception and well worth the effort.

Put aside any thoughts of melon-size iceberg or knee-high romaine flourishing in your cellar or parlor. The types to grow under lights are the tender and leafy varieties, such as bibb and buttercrunch, oak leaf or salad bowl, to name only a few highly prized greens.

Also, be realistic in your expectations. While you won't feed a family of six , growing lettuce indoors is a sensible project for a couple.

Virtually the only major investment is for a fluorescent stand. But before you embark on any committed lettuce-growing project, it might be best to try it out with a small fluorescent stand to see if you like what you're doing.

A small model available at seed houses, nurseries, and hardware stores is 14 inches wide, 24 inches long, and 30 inches high, and costs about $60, complete with two lights. If your trial run pleases you, you then can escalate to bigger stands. I have a built-in stand along one wall of my dining room that serves as a showcase for flowering plants as well as a lettuce patch.

Aside from the stand, all you need are flats, seeds, potting soil, water, a small package of fertilizer, patience, and careful attention to a few fundamentals.

One of the joys of lettuce, such as cleopatra, is its infinite variety. Look up lettuce in a seed catalog and you'll find myriad types and shapes, with colors ranging from blondish to ruby red. Seeds from France, Britain, Italy, and other countries, now easily available, have added a touch of romance to growing lettuce indoors.

I have excellent results with buttercrunch, but it takes 65 days to grow the dark green leaves with delicate white ribs that are an epicure's delight. If you're in a hurry with the experiment, you're better off with oak leaf or salad bowl greens, which take about 45 days.

The fluorescent stand comes equipped with a plastic tray. While you can grow plants directly in the tray, it's better to put your potting soil in a small flat with a perforated bottom and place this in the tray. I acquire such flats at a nursery when I buy plants or seedlings. The holes in the bottom keep the flat from becoming waterlogged. Water runs through the flat and into the tray. Since abundant watering is a must for lettuce, this system provides a good control.

Fill the flat to the top with potting soil. With the tip of a pencil scratch three furrows across the flat from side to side about 2 inches apart, cover lightly with the soil, dampen thoroughly, and you're on your way.

Now comes the most important part of the experiment. Disaster strikes right away unless you pay attention, and I speak from experience. Because of the warmth and controlled conditions, lettuce germinates quickly indoors, sometimes in only two days.

It is essential that the sprouts be very close to the lights when they come up. By close I mean no farther away than an inch. Some fluorescent stands come equipped with chains that enable you to raise or lower the lights. Another way is to put blocks under the tray to raise it to the desired distance from the lights.

If you fail to do this, the sprouts will instantly become leggy, or ''drawn, '' as they reach toward the lights. This, you should remember, is their ''sun.'' When this happens, you might as well start over again rather than expect anything from those weaklings.

After you've established sturdy sprouts, there is not much more to do except to water, fertilize, and wait. Keep the flat moist even after the lettuce is fully grown and you are cutting it. Also, keep fertilizing about once a week. I get good results with a 15-30-15 fertilizer applied in a solution of one-eighth teaspoon per quart of water.

As the plants grow, you adjust the distance from the lights to accommodate the size, but it is important nevertheless to keep the tops of the leaves close up to the tubes. Turn the lights off at night when you go to bed, but otherwise they should never be turned off.

Your one-flat experiment will provide you with several salads if you cut only the large leaves and allow the others to keep growing.

With my built-in stand, 6 feet long by 6 feet tall and with 4 shelves, I grow enough lettuce on just the bottom shelf for all the salads my wife and I need all winter.