Coriandrum sativum is a fast-growing annual with two common names: the leaves are the herb cilantro or Chinese parsley and the seeds are the spice coriander. The International Herb Association designated this plant as their Herb of the Year™ 2017. The leaves resemble European parsley leaves in shape but this plant has a pungent, sweet-musky odor and taste that some people don’t like. Descriptions of the flavor of the leaves vary from citrusy with a biting tang, to soapy, to that of crushed bed bugs. The scientific name is derived from the Greek koris (bug or gnat) that supposedly refers to the similarity in odor. The dried seeds are generally described as sweetly aromatic, nutty and spicy.
This member of the carrot or parsley family (Apiaceae) is native to southern Europe and Asia but has spread to many other parts of the world. One of the oldest know herbs, it was grown in ancient Egyptian gardens and its seeds have been found in Egyptian tombs. It has been cultivated for thousands of years in India and China. It was introduced into Mexico and Peru by the Spanish conquistadors. The Chinese used the herb in potions to provide immortality, while in other cultures it was considered an aphrodisiac or appetite stimulant. The seeds were used medicinally, for making teas as a digestive aid and its reputed sedative effect on some people. The oil from the seeds was used to disguise the flavors of other medicines, used in ointments for painful rheumatic joints and muscles, and is reputed to have cholesterol lowering properties.
Cilantro is a cool season crop that tends to bolt (go to seed) in hot weather but will not survive a hard freeze. The young plants produce wide, flat leaves but when the plant begins to bolt, it produces lacy and fern-like leaves along the flower stalk. The foliage grows 12-18” high, and the flower stems reach 2-3 feet. The clusters of little white or pale pink flowers are borne in umbels, and are very attractive to small beneficial insects such as adult syrphid flies and parasitic wasps that consume the nectar.
There are only a few cultivars available, so you may not have many choices. While some of these, such as ‘Santo’ and ‘Caribe’ may be less susceptible to bolting, none hold well under high temperatures and long days.
A growing season of at least 100 days in necessary for a seed crop; the foliage will be ready in 45-80 days. Cilantro grows best in well-drained soil in full sun but will tolerate very light shade. It can also be grown successfully in containers.
Plant seeds in early spring (at the same time you would plant lettuce). Place the seeds 1/4-1/2 inch deep in rows about a foot apart. Cilantro does not transplant well because of its long taproot. Thin the well-established seedlings to 3-6” apart. For seed production, thin to 12” apart. Make successive sowings at 2-3 week intervals (if growing the plants for their leaves) for a longer harvest. Summer plantings are not recommended because the plants generally just bolt before producing much. For a fall leaf crop, seed in mid-August. Cilantro reseeds readily if the plants are allowed to go to seed.
Keep evenly moist throughout the growing season. Reduce irrigation when the seeds are nearing maturity. Cilantro does not have any serious pest problems, although some commercial growers have reported problems with a bacterial leaf spot.
Pick fresh leaves any time after the plants are about 6” tall but before they bolt (the leaves may develop a disagreeable flavor at this stage). Removing the older, outside leaves will encourage the plant to produce new leaves, but the younger leaves have more intense flavor. Whole plants can be cut off as a bunch at an inch above the ground, and then allow the plant to regrow for a second cutting. Cilantro leaves are best used fresh, but can be frozen or dried (although the dried leaves lose much of their flavor). Cut leaves can be stored in the refrigerator for about a week or place a “bouquet” of leaves in water to maintain freshness in the refrigerator.
Harvest the seeds when they turn a light brown and the entire plant is dried, usually 2-3 weeks after flowering. Cut the stems before much shattering has occurred and hang the plants in a warm, airy place to dry. Because many of the seeds will fall out, place the cut stems over a cloth to catch any that fall or put the stalks inside a paper bag. Make sure the fruit is thoroughly dried, which develops the flavor of the seeds. To save seed for your next crop, just store the whole pods in a cool, dry location. For culinary use, rub the pods to release the seed from the seed coat. The dried seeds can be stored for months in an airtight container in a cool, dark place.
Dig the roots of plants that have not gone to seed in the fall for use in Thai and Vietnamese cooking.
Fresh or dried cilantro leaves are an essential ingredient in many Latin American, Caribbean, and Asian (especially Thai and Vietnamese) dishes. Cilantro is often added to Mexican salsas and meat dishes, and is used in some Chinese soups. Arabic cooking uses both leaves and seeds, in pickles, curries, and chutneys. When cooking with cilantro, add it at the very end to prevent overcooking it.
Coriander seeds can be used whole or ground in cookies, baked goods, soups, casseroles, or sausages. In northern European countries the seeds are sometimes baked in bread; in England they are used to flavor liqueurs. Coriander is an essential ingredient of the various curry powders and masala mixtures of India.
– Susan Mahr, University of Wisconsin – Madison