When to Plant String Beans in North Carolina

String beans, more commonly called "snap beans" today, are a frost-tender vegetable crop that is most easily planted in mid spring in North Carolina. Provide a fertile, moist and well-draining soil in a location that receives at least eight hours of direct sunlight daily.

The Tarheel State is generally discussed as three garden regions: the western mountains, the Piedmont, and the coastal plain. The mountains have the coldest winters, with the last spring frosts occurring as late as April 25 through May 5, after May 15 on the highest peaks in Avery County. The rolling foothills and woodlands of the Piedmont are at lower elevations and last spring frosts happen between April 10 and 20. The lowland plains in the far eastern counties enjoy the mildest winter and earliest spring; last frost occur between March 26 and April 10.

String beans are sown as seeds in North Carolina in spring immediately after the last expected spring frost date. According to "Month-by-Month Gardening in the Carolinas," the soil temperature at the 2-inch depth needs to be at least 50 degrees F. According to North Carolina State University Extension, string beans are sown around April 15 in the central Piedmont and higher elevations of the coastal plain,

Two weeks prior to the last expected spring frost date in your area, till the vegetable garden soil to a depth of 8 to 12 inches. Add 2 to 5 inches of organic matter like compost or well-rotted manure and incorporate it thoroughly. Allow the freshly tilled soil to naturally settle and warm in the sun prior to seed sowing after the threat of frost ends.

String beans may also be sown again in mid August in the Piedmont and late August across the coastal plain. The plants mature in the warm weather across September and produce pods for harvest up until killing frosts anytime from mid October to mid November.