Coriander

Sowing: Coriander's taproot resents transplanting, so seed is sown directly, about 1/4 to 1/2 inch deep, in full sun or light shade where summers run hot, once frost danger has passed; seedlings are later thinned to roughly 3-6 inches apart. Succession sowings every one to three weeks keep a steady leaf harvest coming, and a fall planting needs about 60 days to reach leafy size or 100 days to mature seed before the first frost.

Watering: The plant needs evenly moist, well-drained soil to grow into a robust plant; irregular watering or dry spells push it to bolt and flower before much leaf has formed, so watering is only eased back once the seed heads are nearing maturity.

Coriander is prone to bolting, shifting from producing broad young leaves to lacy, fern-like foliage on a flowering stem well before a gardener would want it to. It has few serious pest problems, though commercial growers have reported bacterial leaf spot, and the plant shows resistance to humidity-related stress.

Leaves: Fresh leaves can be picked any time after plants reach about 6 inches tall and before they bolt, since flavor turns disagreeable once flowering starts; snipping the outer leaves encourages regrowth, or whole plants can be cut an inch above the ground for a second flush. Cut stems keep unwashed in an airtight container in the refrigerator, or stand in water covered loosely with a bag and changed every two to three days, lasting about a week; drying the leaves loses much of their flavor.

Seeds: Seed is ready once it turns light brown and the whole plant has dried, usually two to three weeks after flowering, and stems are cut before much shattering occurs. The cut stalks are hung in a warm, airy place over a cloth or inside a bag to catch falling seed, which finishes the drying that develops their flavor; whole pods keep in a cool, dry place for next season's sowing, or can be rubbed free of their coat and stored airtight in a cool, dark spot for months.

Roots: Roots of plants that have not yet gone to seed can be dug in fall for use in cooking.

Culinary: Leaves, stems, seeds and roots are all edible, with fresh cilantro leaves used in Latin American, Caribbean, Mediterranean and Asian dishes, added to cold preparations like salsa or stirred into hot dishes at the end of cooking. Dried coriander seed is generally toasted and ground for flavor, used to make beverages including gin, and as a food preservative, while the crushed or minced root can stand in for garlic in some Southeast Asian cooking.

Ornamental and wildlife: The umbels of small white or pink flowers attract beneficial insects such as syrphid flies and parasitic wasps, and the plant serves as a host for swallowtail butterfly caterpillars; the seeds are also used in potpourri and sachets.

Medicinal: In various traditional practices coriander seed has been used to make digestive teas and was credited with a sedative effect, while its oil was used to mask the flavor of other medicines and worked into ointments for aching joints and muscles; in Chinese tradition it featured in potions said to grant immortality, and elsewhere it was regarded as an aphrodisiac or appetite stimulant.

Coriander is native to the Mediterranean Basin and the Middle East, with records of its use dating back to the Ebers papyrus of about 1550 BCE and seeds recovered from ancient Egyptian tombs. It has been cultivated for thousands of years in India and China, and Spanish conquistadors later introduced it to Mexico and Peru.