Cilantro grows best in an area that is sunny but offers some afternoon shade. Do not plant cilantro outdoors until the danger of frost has passed. In addition, avoid planting cilantro near fennel, because the fennel will suffer. Like other herbs, cilantro grows best in soil with a pH, or level of acidity and basicity, of 6 to 7. The soil should also be rich and well-drained. Work in 2 to 3 inches of organic amendments to a depth of about 8 to 12 inches to help with moisture control. Such amendments include cracked pea gravel, fine pine bark or leaf mold.
Because cilantro has an extremely sensitive taproot, select a place to grow your cilantro seeds that will not require you to transplant it. For example, plant cilantro seeds directly into a garden, or plant them in peat pots you can put directly in the garden. If planting a seedling, do not disturb the root when you remove the starter plant from the nursery pot. To help with this, select a pot at the nursery that includes plenty of room. You also can grow cilantro in a planting container, filling the pot about two-thirds full with a good-quality potting mix.
When sowing cilantro seeds, place the seeds 1/2 inch deep. When planting outside, make sure the bed is raised to assist with drainage. If planting a seedling, dig a hole or choose a container that is large enough to hold the starter plant. Plant the cilantro seedling at the same depth it was in the nursery pot.
Water your cilantro plants thoroughly and allow the soil to dry out slightly between watering times. Water the plants in the morning so that the foliage has the opportunity to dry off during the day, thus preventing fungal diseases. In addition, thin your cilantro plants to 4 inches apart as they begin to develop. Put mulch such as wood chips or black plastic on the soil to help the soil retain moisture and keep the cilantro roots cooler as well.