To harvest cilantro, cut the leaves when the plant is short and before a tall stalk appears. After the stalk appears, the plant is finished growing and its leaves are bitter, but the seeds are available for harvest.
- Pinch back plants
When cilantro plants are young, cut off the main stem's top portion. This encourages the plant to grow fuller, and it prolongs seed production.
- Harvest new leaves
Cut the cilantro plant's new, smaller leaves shortly after they develop. The lower, larger leaves are not as flavorful. Frequent harvesting is recommended because cilantro grows quickly, and it produces seeds, or bolts, within two to three weeks after it matures. Use harvested leaves immediately, or freeze them in a plastic bag. Drying cilantro is not recommended because the dried herb retains little flavor.
- Collect coriander seeds
Allow the seed head to develop once the plant bolts. Cut off the head when it is brown, and place it in a paper bag. The seeds fall off the head as they dry, and they are ready for use a few weeks after harvest. As an alternative, leave the head on the plant, and allow the seeds to drop into the garden if you wish to self-sow new plants.