Although it is available year-round in most markets, prime season for zucchini is May to August. This is why it is often called summer squash.
Handle zucchini with care as they are easily damaged. Look for a moist stem end and a slightly prickly, yet shiny skin as indicators of freshness. Ideally, green zucchini should be no more than 6 inches long and one to two inches in diameter, with firm skin free of cuts or bruises and at least one inch of stem still attached.
Baby fingerling zucchini is a popular new item in the markets as well as with home gardeners who have the luxury of picking them at any time. Fingerlings can be steamed, sautéed, or pickled whole.
Another favorite with home gardeners is zucchini blossoms, stuffed or not, dipped in egg, spices, and flour, and fried golden. Picking the flowers actually encourages more fruit. Some markets are now carrying squash blossoms, often with a tiny zucchini attached. Look for bright, perky flowers with no wilting. Flowers should be sprinkled with water, wrapped gently in paper towels and refrigerated. Use as quickly as possible.
Store zucchini in a plastic bag in the refrigerator crisper drawer four to five days and do not wash until just before you are ready to use it. At the first sign of wilting, use immediately. Softness is a sign of deterioration.
Cooked zucchini should be covered and refrigerated up to two days.
To freeze, slice zucchini into rounds, blanch for two minutes, plunge into cold water, drain, and seal in airtight containers or baggies. Frozen zucchini can be kept for ten to twelve months.