In the Southeastern United States, sweet potatoes are traditionally cured to improve storage, flavor, and nutrition, and to allow wounds on the periderm of the harvested root to heal.[21] Proper curing requires drying the freshly dug roots on the ground for two to three hours, then storage at 85–90 °F (29–32 °C) with 90 to 95% relative humidity from five to fourteen days. Cured sweet potatoes can keep for thirteen months when stored at 55–59 °F (13–15 °C) with >90% relative humidity. Colder temperatures injure the roots.[