Sweet potatoes need to be cured, starting on harvest day. To cure them, keep your sweet potatoes at 85 to 90 degrees for five days. During this time, the sweet potato will grow a second skin, which is an incredibly effective seal.
After curing, you can leave a sweet potato on the kitchen counter for several months without noticeable moisture loss. Without curing, the sweet potato will only last a month or two in storage. Curing also initiates flavor development. Cure & store a few mo then eat.