Basil uses

Gardening. Though perennial in warmer climates, basil is a frost-sensitive annual in much of the United States. Basil can be planted from seed or rooted from cuttings. Since lemon basil does not seed, propagation by cutting is the only option.
Pruning encourages bushy growth, and basil should be pruned and deadheaded regularly. Some gardeners treat basil as an ornamental, as well as a culinary plant. Basil can sometimes be successfully transferred indoors for the winter.
Food and other uses. Fresh Mediterranean basil leaf is a principal component of pesto alla Genovese (green pesto) and also appears in pesto rosso (red pesto), which includes tomatoes as well as basil. Basil leaf is also used as a seasoning in tomato sauce, pizza, Insalata Caprese, salad dressing, and cooked vegetable dishes. Dried basil leaf is found in the mixed spice called "Italian seasoning," and sometimes is a component of bouquet garni. Thai basils, which differ from Mediterranean basils, are used in Thai green curry and as a garnish.
Basil is also used in desserts, including basil ice cream and sorbet, custard and zabaglione. Basil seeds are used to thicken the consistency of certain Thai foods. Essential oil of basil is used in perfumes.
Preservation. Basil should be harvested periodically to encourage regrowth, but it is especially important to do a final harvest before the temperature drops, as the plant is not hardy. After harvesting, many gardeners prefer to freeze basil, rather than dry it, because the flavor and color are better preserved. One can simply strip, clean and freeze the leaves on baking sheets before transferring them to bags.
Alternatively, chop the leaves with olive oil and, if you like, the other pesto Genovese ingredients except the cheese, and freeze in bags. You can also process the leaves with olive oil or a little water and freeze initially in ice cube trays, then transfer them to bags. To dry basil, bind stems of several plants together and hang in a dark, dry place.