The ideal time to plant potatoes is no earlier than two weeks before the last frost date that is expected for the area or as soon as the ground is workable. Potatoes are a cool-weather crop, and they can withstand the light frosts that come at the end of winter.
Potatoes don't perform well in extremely hot temperatures, so early-season varieties are best for southern climates. Potatoes grow best when the soil temperature is between 60 and 70 degrees Fahrenheit, and they stop growing when the soil is at 80 degrees or higher. Adding a 6-inch layer of straw mulch to a potato bed lowers the soil temperature by several degrees and extends the growing season.