Choose a sunny spot with afternoon shade. Dig a hole twice the diameter of the cilantro plant's container and 2 inches deeper. Add 2 inches of compost or manure to the bottom of the hole.
Remove your cilantro plant from its container and loosen the roots, taking care not to damage the tap root. Place the plant into the hole, and refill with the removed soil, gently tamping down the soil around the plant with your fingers.
Sprinkle 1 teaspoon of Epsom salt around the plant, and work it gently into the top of the soil. Epsom salt contains magnesium, which helps roots establish. Water the plant thoroughly, and add 2 inches of mulch to hold in moisture and keep the roots cool. Water the plant every other day for two weeks, then water as needed.