How to Care for Cilantro Plants

Cilantro (Coriandrum sativum) has delicate leaves that pack a strong, aromatic punch. Grown either in containers or directly in the ground, this annual is ready for harvesting 45 to 70 days after seeds have been sown. For the biggest harvest, provide cilantro plants with the proper daily care.

Cilantro thrives in full sun. The sun's light and heat encourages the herb to produce more of its fragrant oils, and this enhances both the smell and flavor of cilantro. For the best results, give cilantro a minimum of six hours of direct sunlight every day. For cilantro grown directly in the ground, keep nearby trees and shrubs from casting shadows on the planting site. For cilantro grown in containers, move the pots to an area that maximizes its sun exposure. As an example, place cilantro grown in a container indoors on a west- or south-facing windowsill.

Water cilantro sparingly. Too much moisture is bad for cilantro, and plants suffer when kept in humid or damp growing conditions. When watering container-grown cilantro, use enough water that some moisture trickles out of the drainage holes in the bottom of the container. When watering cilantro grown directly in the ground, apply enough irrigation to moisten the soil to a depth of 6 to 8 inches. After watering, allow the soil to dry out completely before watering again. Seedlings require about 1 inch of water per week.

Excessive fertilization encourages rapid growth, but it also decreases the aroma and flavor of cilantro. Fertilize cilantro sparingly, once after germination and again halfway through the growing season approximately 20 to 30 days after germination. Use just 1/2 teaspoon of either 21-0-0 or 34-0-0 fertilizer for every square foot of gardening space. Water the herbs after fertilizing them to help dissolve the fertilizer and carry the nutrients down into the soil.

Cilantro may occasionally suffer from attacks by leafhoppers and other soft-bodied pests, such as mites and aphids. These insects suck on the herb's sap and, if not controlled, can cause wilting or foliage loss. Spray down cilantro with a jet of water from the garden hose to knock away aphids and other pests. This is often enough to keep pest populations at levels too low to cause damage. If pests persist, mix a homemade insecticidal soap by adding 2 tablespoons of liquid dish soap to a quart of water. Spray the solution onto pests to kill them on contact.

Slugs and snails may also snack on cilantro's low-hanging foliage and stems. Symptoms include missing leaves and telltale trails of slime. Sprinkle a 1/2-inch-wide band of food-grade diatomaceous earth around cilantro plants. When the slugs or snails crawl over the diatomaceous earth, the natural powder cuts and kills the pests.

Once cilantro's leafy stems reach a length of 4 to 6 inches, the herb is ready for harvesting. Harvest stems on an as-needed basis to encourage the plant to continue to grow, or harvest the entire plant by cutting all the stems at the base of the herb.

Rinse the harvested leafy stems under cool running water to clean them if you are using them immediately. To store your harvest, place the stems in a jar of water and put the jar in the refrigerator. Refresh the water every three days. Using this method, cilantro will keep for up to a week.