Sweet potatoes are native to warm, tropical regions and a long season root crop. They are often referred to as “yams” to distinguish them from white potatoes.
Sweet potatoes, however, are not yams; botanically, they are quite different. Yams belong to another cultivar group, have rough, scaly skin and are very low in beta carotene. In contrast, sweet potatoes have smooth skin and are rich in beta carotene among other nutrients.
Because the two words are used interchangeably in the United States (and Canada), the U.S. Department of Agriculture (USDA) requires “yam” labels to always be accompanied by “Sweet Potato” to alleviate confusion.
Types & Varieties
There are hundreds of varieties of sweet potatoes and not all are the familiar orange color. Some varieties are purple, others are white, and many are variations of the orange coloring we typically see. The most popular variety planted in North Carolina, the top producer of sweet potatoes in the United States, is the Covington. Others varieties include Bayou Belle, Bellevue, Bonita, Burgandy, Murasaki, and Orleans.
Sweet potatoes are propagated from ‘slips’ or vine clippings and grow best in warm weather. Once the roots have spread, minimal weeding is required.
Plants are not drought-tolerant, so irrigation is needed if extended dryness occurs. Two to three weeks before harvest, irrigation is typically stopped so vines begin to dry.