Sweet Potato Culture
Bountiful yields and a large return for very little work, are afforded by sweet potatoes, which are native to the Carribbean region of the New World.
Sweet Potatoes need really warm conditions to flourish. They should be set out into the garden not just when danger of frost has passed, but when soil temperatures are about 70 degrees Fahrenheit. In most areas this will be two to three weeks after last frost date.
Sweet potatoes prefer to be set into an acid-to-neutral soil, none too rich. Do not add much manure or rich compost unless the soil is very poor, or the plants are apt to produce luxuriant leaves but few tubers until quite late. Set the plants at least two feet from neighboring sweet potato plants.
The plants are very drought-tolerant if the air is not too dry, but will do better with regular water. Very little care is required other than keeping weeds to a minimum. A thick mulch is beneficial. The vines may range several feet in long-season areas.
Tubers are traditionally harvested after the early light frosts have blackened the leaves, but before the stems have been killed to the ground. Lift the tubers, which usually form just in the area where the original plant was set, but may occasionally form under the runners. Allow tubers to cure in warm sunshine if possible, even for a few days if the weather is mild, but do not allow them to be touched by frost. Continue to cure the tubers for a week to ten days in very warm, humid conditions. (80 degrees is ideal, but can be hard to achieve in cool autumn weather.) The sweets need this curing period to transform starches to sugars, and to make the changes needed to store through a winter. Store in relatively warm conditions, preferably about 60 degrees, and never in a refrigerator or root cellar.
If tubers can be made to store all winter, new plants can be had by planting one into warm soil, or immersing halfway in water in a warm, sunny window. Alternatively, cuttings of the sometimes magnificent foliage can be taken indoors before fall frost. There they will grow all winter long in a sunny location, doing double duty as an attractive houseplant before being cut up, rooted indoors, and set outside the following spring.