ON HOT AUGUST evenings in the Pittsburgh neighborhood of my childhood the old Italian men would be out in their gardens watering tomato plants that they had affectionately tied with rags to sturdy wooden stakes. Puffing contentedly on a cigarillo, they would mumble in Italian to their tomato plants, as if good-naturedly encouraging the plums, better boys and beefsteaks to go on to become the best spaghetti sauce in the Ohio Valley.

No reluctant weekend gardeners, these immigrants worked their tomato, pepper and garlic plots carefully, as their small gardens were a tangible connection with a fondly remembered old-world past. They started their tomatoes from seed early in spring in their kitchen windows, and waited anxiously for the passing of the final cold spell around Memorial Day so that they could set out their plants.

As a child I was warned to keep my hands off the sacred plum tomatoes that were specifically reserved for sauce. Others I could eat at random as they ripened. To eat a red juicy tomato plucked hot off the vine with a few shakes of salt was sheer joy; and a thick slice of beefsteak with mayonnaise between two slices of fresh Italian bread was heaven!

As Labor Day approaches in my old neighborhood, the streets are full of delicious aromas of tomatoes being canned. Down in her canning cellar Molly Giacobine takes a pot full of freshly scalded tomatoes, peels them and puts them into a large 10-quart black enamel pot. "A handful of salt, a handful of sugar, some peppers and spices to give it some gusto. I never go wrong," she says proudly.

Later in the cool of the evening we eat a delicious salad of lightly chilled tomatoes with scallions and olive oil as the main course of a summer dinner.

Over the past 60 years Americans like myself have developed a passionate love affair with the tomato. In 1920, the average American ate 18.1 pounds of tomatoes a year. Today we each eat 50 pounds, and the tomato has become a national market crop worth nearly $1 billion.

The tomato has had a long history in the United States. Originating in South America, where Indians displayed little interest in cultivating it, the tomato was brought back to Europe by Spanish colonizers. For two centuries the tomato was used as an ornamental plant in Spain, Portugal and France.

According to food historians, the Italians were the first to eat and cook tomatoes; and Thomas Jefferson, a pioneer in so many areas, first planted tomatoes in Virginia in 1781. Yet throughout the 19th century Americans remained wary of the "tomata" out of fear that it was poisonous or caused cancer. With the massive immigrant exodus of Mediterranean people to America after 1900, the tomato fortunately became a cherished and respectable table food.

Alas, most of today's tomatoes scarcely resemble those raised in my Pittsburgh back yard or those Thomas Jefferson cultivated at Monticello. Most are rubbery, tasteless, squarish balls developed and grown by agribusiness so that they won't be hurt by automatic tomato pickers, roll back down tilted conveyor belts, or bruise after they are cased in plastic and shipped across the country.

So those of you who have cherished your tomatoes, watered them and fought those ugly green worms who would destroy your beauties, take heart. Those hot August nights are here. You city dwellers, look to the roadside stands on Maryland's Eastern Shore and to your local farmer's market. Good tomatoes are easy to find at this time of year.

Tomatoes are a reasonably priced source of Vitamin C and are fairly rich in phosphorus, magnesium and Vitamin A. Herewith are a few tomato dishes to help you celebrate a good harvest: TOMATO SALAD ITALIAN

Rub a large salad bowl with raw garlic. Slice several large, well-ripened tomatoes into large chunks. Add several sliced scallions and two anchovy fillets. Stir well in the bowl with a dash of pepper. Add olive oil and wine vinegar to taste. EASTERN SHORE RATATOUILLE (4 to 6 servings) 1/3 cup olive oil 2 cloves garlic, sliced 2 medium-sized onions 4 cups sliced zucchini 4 green peppers, diced 4 tomatoes, peeled and sliced Salt, pepper and oregano to taste

Heat the olive oil in dutch oven or deep skillet. When the oil is hot, add garlic and onions. Add zucchini and green peppers. Stir mixture over moderate heat and add peeled and sliced tomatoes. Add salt, pepper and a dash of oregano and cook, covered, over low flame 45 minutes. FRIED TOMATOES 4 ripe tomatoes, cut into 1/2-inch slices Seasoned bread crumbs Dash caraway seeds Vegetable oil Soy sauce or italian dressing (optional)

Dip cut tomatoes into seasoned bread crumbs and add a dash of caraway seeds to each slice. Heat vegetable oil until hot and cook 8 to 10 minutes or until golden brown, turning once. Try varying the recipe by marinating the slices beforehand in soy sauce or italian dressing.