Judging from the number of questions I've received in the past two weeks, readers are very aware that now is the prime time to establish and care for a lawn. Taking steps this month is the secret to making your turf beautiful. A cool-season turfgrass will grow vigorously from now into winter.

There are more than 500 classes of plants within the grass family, but only a few are suited to lawns. Among them are turfgrasses, which have been used as such for about 1,000 years. They help control erosion and dust, improve soil and water quality, dissipate heat and noise, reduce glare, decrease numbers of pests, and reduce fire hazards.

Turfgrass must survive regular cutting at heights of one to four inches, be perennial, stay green most of the year and grow into a tight carpet that withstands foot traffic. Grasses that fit these criteria are divided into two types, warm season and cool season.

Warm-season grasses are brown in winter and don't begin growing until average outdoor temperatures are more than 60 degrees. In fact, they love it when it's hotter. We live on the northern cusp of hardiness for warm-season grasses. The only warm-season variety that it is practical to plant here is zoysia, in the spring.

Cool-season grasses are more suitable for our region. They stay green during cool temperatures and brown during drought and heat. They hold chlorophyll longer and withstand winters better. Some stay green through winter.

Here are the steps for lawn installation and rejuvenation of cool-season turf:

Installation

Check your soil's pH and basic nutrients with a test offered for a nominal fee through your county cooperative extension service. Adjust the pH and nutrient levels according to test results.

An area with no existing grass gives you the opportunity to create the perfect medium for a healthy lawn. You'll need a flat surface that drains and is level enough to mow; a shovel or rototiller; a garden rake or wide grading rake for leveling the tilled soil; and lots of fine-textured compost (three or more cubic yards per 1,000 square feet of lawn area). The area must receive at least six to seven hours of sun daily.

Lay compost one to two inches thick over the area to be seeded. With a shovel or rototiller, dig the organic material into the top four to five inches of soil. Once it is well mixed, rake the surface. Skim off any large stones, sticks and roots, fill and level any low spots and cut down higher ones to ensure a smooth surface.

When the area is level, fertilize and seed as recommended below for lawn rejuvenation.

Rejuvenating a Lawn

Starting with a bare area and tilling it offers the opportunity to incorporate much more compost than when rejuvenating an existing lawn. With an established lawn, the only step you can take to get organic material into the soil beneath is to aerate the lawn by punching a lot of holes in it.

Get a machine called a plug aerator at an equipment rental company. Don't use one with solid tines: They allow penetration of water and nutrients, but actually compact the soil where each tine penetrates. Since you have to rent for a minimum of a half day, go over the lawn three or four times--more, if possible--but never when it is wet.

Condition the site with compost that's fine-textured enough to fill the aeration holes. Sprinkle it about a half an inch thick over the holes, making sure you don't cover healthy turf. Your own compost is best. Otherwise get Compro, Leafgro or a comparable material.

If the compost is not fine-textured and dry enough to apply with a broadcast spreader, use a shovel. You might spread about five bags per 1,000 square feet if your lawn has many bare areas, and as few as one or two bags if the grass is thick. If the soil is hard clay, aerate and apply compost every spring and autumn for a few years.

Using a lawn spreader, apply high-nitrogen dry fertilizer this month. Read the label for application rates. I recommend a product that is 40 percent to 50 percent organic or labeled to have some percentage of slow-release or water-insoluble nitrogen (WIN). The slower-release and organically based materials are somewhat better for the environment because they don't wash through the soil as quickly. The organic materials are usually the slowest release. Soil test results may offer more recommendations.

Brands I've used are Greenview Green Power Lawn Fertilizer 30-4-4, Lofts Lawn Food 28-3-8 and Super Turf Assurance Lawn Food 28-2-8.

Now spread four to five pounds of seed per 1,000 square feet on established lawns, twice that amount on a bare area. The exact quantity depends on the type of grass. You should be given that information at the garden center when you purchase the seed, or it may be offered on the label.

Pick a cool-season seed, choosing between two styles--compact, turf-type tall fescues, or fine-leafed types, such as bluegrasses, fine fescues and perennial ryes. Don't mix coarser-textured tall fescues with fine-bladed grasses in a new lawn. Seeding an existing lawn, you probably won't know what's there already. So choose one depending on your needs and desires.

Tall fescues are wear-tolerant, disease-resistant and mowed three to four inches high. Fine-textured bluegrass, fine fescue and perennial rye are more prone to disease, but softer to the eye and touch. They can be mowed to a height of 2 1/2 inches and maintain a lush appearance.

Compact, turf-type tall fescue blends that I've used are Compact Blend and Confederate. But any another blend of three or more seed varieties is fine. For a finer-textured Kentucky bluegrass/fine fescue/perennial rye mix, try Blue Ribbon Shade for light shade (five to six hours of sun), or Scotts All Purpose, Proscape Superior Sun and Shade, or any of the hundreds of other brands available. Do not buy generic seed.

After you aerate and spread compost, fertilizer and seed, ensure their proper distribution and break up the soil plugs taken from the holes in your lawn. Do this by walking an upside-down wire rake over the surface. Then water. Without it, nothing grows. Sprinkle seeds with water whenever the surface appears dry.

Lerner is president of Environmental Design in Capitol View Park, Md. His e-mail address is lernscap@erols.com