Sweet potatoes can be grown almost anywhere. The orange-fleshed sweet potatoes are the most familiar, but sweet potatoes can be white, yellow, and even purple. Since the vines root wherever they touch the ground, a few plants can produce a generous harvest. Once the foliage starts to turn yellow, the potatoes should be ready to be dug up. If the foliage is hit by a frost, the tubers are probably still fine. Just don’t let them sit in the ground too long after the tops die back or they could start to rot. Be gentle when digging. Sweet potato tubers grow close to the surface. Their skins are tender and can be damaged and bruised easily.