Cilantro, an herbaceous annual popular in herb gardens around the country, grows natively in southern Europe and Asia, and requires cool temperatures to thrive. The plant produces seeds known as coriander and pungent, sweet leaves, also known as Chinese parsley, are valued for their use in cooking. Cilantro requires 45 to 80 days of growth before harvesting the leaves and up to 100 days before harvesting the seeds. The plants bolt, or drop leaves, if exposed to very warm temperatures and cannot tolerate frost. For this reason, planting in the correct location and at the correct time is an important part of growing cilantro plants successfully.
Plant container-grown cilantro during spring, just after the final frost of the season. Choose a location that receives light shade throughout the day. Apply a 2-inch layer of compost and use a garden tiller to amend it into the soil to increase fertility.
Spread a 1-inch layer of mulch over the soil surrounding cilantro to suppress weeds, insulate the soil and improve moisture retention. Replenish the mulch as often as necessary to keep it about 1 inch thick throughout the growing season.
Water cilantro plants once per week during the first two months of growth to keep the soil from drying out completely. Reduce watering frequency to once every 10 days thereafter. Do not allow standing water to accumulate, or the plant will rot.
Harvest coriander seeds from flowers that have faded to a brown color and turned into seed heads. Remove two to three seed heads at each harvest to prevent damaging the plant. Dry the seed heads in a paper bag for one week, and then keep in the refrigerator until ready to use.
Fertilize cilantro immediately after harvesting the seeds to replenish the lost nutrients. Use a balanced 10-10-10 NPK fertilizer to provide proper nutrition for additional flowering. Apply at the rate recommended by the product's manufacturer.