Annette Williams, age 13, of Lake Charles, La., for her question:

WHAT GRASS MAKES THE BEST LAWN?

A lawn is a plot of ground that has a thick covering of closely cut grass. The variety of grass that a person selects for his or her lawn should be the type best suited for the climate.

The most widely grown lawn grass is Kentucky bluegrass, which thrives in most climates. Bent grass, another common lawn grass, can grow in acid soil that has poor drainage. Bent grass also may be cut more closely than most other lawn grasses.

Lawn grasses that grow well in cool, humid areas include bluegrass, fescues and bent grass. White clover may be planted with these grasses to improve the fertility of the soil.

Many commercial seed mixtures for cool, humid regions contain some ryegrass seed. Such seed grows quickly and produces a lawn rapidly. But ryegrass lives only a short time before it disappears, leaving room for the longer lasting grass in the mixture. Ryegrass is sometimes called nurse grass.

Common lawn grasses in warm, humid regions include Bermuda grass, St. Augustine grass and zoysia grass. Carpet grass and centipede grass are also grown in such locations.

Gamma grass and buffalo grass do well as lawn grasses in dry regions.

Grass can be planted in three ways: seeding, sodding or sprigging.

Seeding is the commonest and cheapest method of planting grass. The seeds can be distributed by hand on most lawn sites. For large areas, you should use a push type seeder.

Sodding is the most expensive way to plant grass. Sections of soil already covered with grass are dug up, carried to the lawn site and laid over the soil. This method is used mostly on small areas or on slopes that would otherwise erode. Sod may be obtained from a garden supply center or a professional landscaper.

Sprigging involves the use of sprigs or small chunks or cuttings of grass.

Sprigs are planted at various intervals, depending on the variety of grass. As the sprigs grow, their low lying stems creep along the ground and root in the soil, thus filling in the lawn site. Sprigging is used chiefly in regions where grass cannot be grown easily from seed.

The care of a lawn involves such tasks as mowing, watering, fertilizing and controlling diseases, pests and weeds.

The height to which grass should be cut depends chiefly on the kind grown.

Watering of laws is unnecessary in most climates because of the normal rainfall. Even during dry periods, a lawn should not be watered more than once a week. A light daily watering may cause weeds or weedy grasses to grow more rapidly than the lawn grass itself.

Most lawns must be fertilized twice a year. The best method is to spread from 15 to 25 pounds of mineral fertilizer on every 1,000 square feet of lawn each spring and fall.

Most diseases of lawns are caused by a type of fungus which can be controlled with fungicides. Pests can be controlled with insecticides while weeds can be kept from spreading by applying chemical weed kiliers or by digging out their roots with a V pointed knife.