A member of the carrot family, cilantro (Coriandrum sativum) is an herbaceous annual native to Southern Europe and parts of the Western Mediterranean region. The leafy green foliage of the plant is a popular ingredient in a number of different styles of cuisine, particularly Mexican. Cilantro can be grown with little effort.
Like most herbs, cilantro does need a fair amount of sunlight, but too much sunlight will quickly cause the plant to flower and begin the end of its life cycle. Cilantro is best grown in the spring in USDA Zones 3 to 8 and in the fall or winter in USDA Zones 9 to 11. The plant will flower once its roots hit a temperature of about 75 degrees F. Cilantro does best in full sunlight in the morning, followed by shade in the afternoon that will shield them from the strong sunlight. Filtered or dappled sunlight, such as the kind that comes from under a larger plant or tree, also works well for cilantro. Gardeners can also mulch the soil as a way of keeping the roots cool for longer.
Plant multiple cilantro plants close together, enough so that the foliage of the plants will shade each other's roots, keeping them from flowering too soon. As a native of the Mediterranean, cilantro prefers a well-drained, even sandy, soil, though it will tolerate a range of different soil types. Cilantro isn't well suited for container growing, and the plants sold in small containers in nurseries often begin flowering immediately after they are purchased thanks to the warm confines of the plastic. Cilantro should be immediately planted in the ground and mulched if necessary. Water on a regular basis, but don't over-water: allow the soil to almost completely dry out between waterings. Don't despair if the plant flowers--you can always plant the seeds and quickly get new cilantro plants. Doing this will also ensure you have cilantro throughout most of the year.
Cilantro can be harvested anytime after it gets to be about 6 inches high (the whole plant may reach heights of up to 3 feet). Pick the outer leaves off the plant as needed, or wait until the plant has gotten to a robust size and pull the whole thing out of the ground as a bunch. Cilantro doesn't keep well for very long, so use within a week unless you plan to freeze it. Wrapping the stems of the herb in a slightly damp paper towel in the fridge crisper will help keep them fresh. Cilantro can be left in the ground to flower and seed. Once the plant begins to brown, its seeds can be harvested as coriander, an aromatic spice used frequently in Middle Eastern and European cooking.