Late summer is a great time to plant more cilantro

Last Updated: 
September 30, 2008

Cilantro photo courtesy of Teresa Welch

CORVALLIS, Ore. - Both temperature and day length have a big influence on whether your cilantro plants will grow tall and leafy or flower and set seed while they are still small.

If you want tall leafy cilantro plants that are slow to bolt, plant cilantro seed in the late summer and early autumn and then again in early spring when days are shorter and temperatures are lower, advises Ross Penhallegon, horticulturist with the Oregon State University Extension Service. In the cooler shorter days of spring or fall, cilantro will grow for several weeks to months longer before flowering and setting seed.

In warm or hot weather, cilantro has a shorter life cycle. In mid-summer, cilantro will bolt into small lacy flowers, then set seeds in about four to six weeks from time of sowing. But summer planting and its associated early bolting does have benefits. The flowers transform into seeds that can be collected, dried and ground into the spice coriander. Plus, cilantro flowers are great for attracting beneficial insects to your garden, especially in the early morning and late evening.

If you do plant your cilantro in the summer and want cilantro leaves, plant seeds or starts in a cool or semi-shaded area in the heat of the season.

Sow cilantro seeds directly into sunny, fertile beds. Plant 10 to 15 seeds per foot of row. Cover the seeds with about a half-inch of soil. Keep the soil moist until germination. Thin plants to eight inches apart with rows 18 to 24 inches apart. If planting cilantro from starts, be careful, as the roots are sensitive to injury. Seeds will germinate with soil temperatures of 55 to 68 degrees. Quite hardy, cilantro plants can withstand temperatures down to freezing.

Commonly used in Latin American, Asian and other cuisine, cilantro has become a popular herb in the United States in the last few years. Its piquant flavor is a favorite in salsas, Thai food, garnishes and in stir-fries.

All parts of the plant are useful. The seeds of the cilantro or coriander plant are ground and used as the spice called coriander, popular in breads, spice cakes, pickling spices and in Asian foods. Coriander root is used in Thai dishes.

Cilantro leaves are best used fresh, as they lose much of their flavor when dried. The small immature leaves have the most flavor. Seeds should be harvested before they drop. The roots are best harvested in the autumn.

Author: Carol Savonen