Although only two or three types of potatoes are found in most supermarkets, there are hundreds of distinct varieties native to Central and South America, ranging in size from tiny marble-size potatoes to huge softball-like tubers. Long and lean or short and squat, with skin that is smooth or bumpy, they come in a variety of colors, including pink, red, creamy white, yellow, and even purple. These regenerative tubers grow from "seed potatoes," which are specially raised by nurseries, are certified disease free, and are readily available through catalogs. Plant potatoes in sandy, acidic soil after the last frost and once the ground temperature reaches 45 degrees.
Planting Potatoes How-To
1. A day before planting, cut large seed potatoes into ice-cube-size pieces; each cube should have two to three well-developed eyes or sprouts. Allow cubes to dry overnight or up to 24 hours in a warm place (this helps fight rot). Alternatively, smaller whole-seed potatoes, about 2 inches long, require no advance preparation and can be planted directly in the ground.
2. Till soil to a depth of 2 feet; add sand, if necessary, to achieve a slightly coarse texture. Dig a shallow trench about 8 inches wide and 6 inches deep. Add a 2-inch layer of pine needles to the bottom of the trench; these further acidify the soil and prevent scab disease.
3. Place seed potatoes at 4- to 12-inch intervals in the trench. Cover with 4 inches of soil. When shoots reach the height of 6 to 8 inches, pull soil into and over trench to cover all but the top 2 inches. Hill up soil around potatoes again 2 to 3 weeks later. Mulch with straw to protect plants from weeds and drought. Water thoroughly during periods of dry weather.
4. Expect a modest harvest of new potatoes about 55 days after the first planting, when you can pull egg-size tubers from the heaped soil. Make sure to leave some tubers to mature into a larger second crop. You will know when the main harvest is ready when the leaves and vines yellow and wither.
5. Dig the main harvest with a spading fork, starting 1 foot from the main stem and working in to avoid injuring tubers.
6. Early cultivars should be eaten within a month to 6 weeks of digging, but mid- to late-season cultivars can be stored safely for as long as 6 months if the tubers are cured. To cure, do not wash them after digging; instead, spread them out in a dark, dry place indoors, and let them dry for a week. Then put the potatoes in paper sacks or shallow open-sided crates, and store them in a dark cool area where the humidity is high.