Sure, you are tired of mowing and watering grass. Come next spring, however, you will be glad you spent a little time the next three months renovating or establishing that cool-season fescue. If you wait until spring to do your seeding and fertilizing, those tender new grass roots will gasp for life when they have to face our heat and humidity.

Successful gardening - lawns, ornamental and edible - starts and flourishes with soil that's conditioned and improved with nutrients and aeration.

``What happens above ground is secondary,'' says Joe Hertzler of Green Guard, a lawn, tree and shrub care company in Williamsburg. ``What goes on below ground is most important.''

Remember, fertilizer is not plant food, even though we often call it just that. Plants make their own food, using water, carbon dioxide and energy from the sun. Instead, fertilizers feed the soil so it can provide more and better nutrients for plants to absorb.

Plants need 16 elements for growth. Three - carbon, hydrogen and oxygen - come from the atmosphere. Among the most essential, or macronutrients, likely to be missing from soil are: nitrogen (N) for vigorous green foliage; phosphorus (P) for healthy root, flower and seed development; and potassium (K) for good plant tissue and resistance to disease, drought and other plant stresses. Secondary macronutrients include magnesium, calcium and sulfur. Micronutrients needed in minute quantities include iron, boron, manganese, copper, zinc, molybdenum and chlorine.

A fertilizer is said to be ``complete'' when it contains all three primary macronutrients. (The percentages of each are listed in order N-P-K.) For instance, a 100-pound bag of 10-10-10 contains 10 percent of each nutrient; the remaining 70 percent of the bulk is filler, which makes it easy for you to spread the fertilizer without burning the plants from too much fertilizer.

An ``incomplete'' fertilizer such as 0-10-10 (no nitrogen) or 0-33-0 (just phosphorus) lacks some nutrients so you can concentrate on a specific deficiency. A soil test is the surefire way to determine deficiencies; guessing can compound problems.

Here are some fertilizer types:

Organic fertilizers - Made from remains or by-products of a once-living organism. Examples: cottonseed meal, blood meal, fish emulsion, manures from horse, cow, pig, chicken and sheep and sewage sludge. Urea is a synthetic organic fertilizer. Cottonseed is good for acid-loving plants such as azaleas, camellias and rhododendrons. Blood meal and fish emulsion are nitrogen rich and can burn plants if used excessively. Manure is considered a complete fertilizer that provides nutrients in slow, low quantities; composted or aged manure is less likely to burn plants. You'll find some organic fertilizers are enriched to provide more nutrients. Organic fertilizers improve the soil's condition, allowing water and air to move through the soil. They also help sandy soils retain moisture.

Note: Lots of nitrogen and potassium is returned to a lawn when clippings are left to decompose naturally.

Synthetic fertilizers - Available in dry or liquid forms, these manufactured substances release nutrients quickly.

Slow-release synthetic fertilizers - These WIN, or water insoluble nitrogen, fertilizers have a high percentage of nitrogen but the slow-release feature does not burn grass or green it quickly. A WSN, or water-soluble nitrogen, fertilizer, dissolves quickly.

Fertilizer with pesticides and herbicides - These fertilizers are made for convenience but the application may not coincide with the problem. There are certain timetables for insect and disease controls so be sure you know those to ensure the product will work.

EXTENSION OFFICES

Virginia Cooperative Extension offices offer free lawn-care literature and $7 soil testing kits. To contact an office: