Cilantro (leaves), matures into coriander (seed). Each round fruit contains two seeds which, if they both sprout, may require thinning. Sow seed 12 mm (1/2 in) deep and thin to cm (8 in) apart. Seeds can take 2 -3 weeks to germinate. Harvest cilantro leaves, leaving some on the plant. Once the flowers develop, plants will stop making more leaves. Plant again in early August for a fall harvest of fresh cilantro. If you let some plants to go to seed for coriander, ensure the seeds are fully dried before sealing up for spice or next year's seed.