How to Grow Potatoes With Old Potatoes

Prepare a garden bed for potatoes in a sunny location that receives six to eight hours of direct sunlight a day. Till to a depth of 8 to 12 inches. Amend with a 2- to 3-inch layer of well-rotted manure or compost. Add 3 lbs. of 10-10-10 fertilizer per 100 square feet. Work the amendments in well with a garden tiller or hoe.

Spread old potato tubers in a single layer at room temperature and high humidity to "green sprout" them. According to the University of New Hampshire Extension Services, green sprouting two weeks before planting encourages sturdy sprouts that grow quickly once planted. Light exposure is necessary but direct sunlight is not.

Cut large tubers into several sections with a sharp knife before planting. Each section requires at least two "eyes," or areas where sprouts emerge. Small tubers, 2 inches to 3 inches in diameter, can be planted whole.

Plant the potato sections in a 4- to 6-inch-deep furrow once the soil has warmed to 45 degrees Fahrenheit. Although potatoes tolerate frost and can be planted as soon as the soil can be worked, they rot easily in cold, wet soil.

Space potatoes 8 inches to12 inches apart in rows spaced 36 inches apart to allow room for growing. Place the cut side down when planting. Cover the potato sections with soil and firm it down with the back of the hoe to secure the them.

Water thoroughly to moisten the soil to a depth of 4 to 6 inches. Water again when the soil feels dry 1 inch below the soil level. Deep watering once or twice a week is preferred to frequent, light watering.

Hill the potatoes by mounding the soil over the bottom 4 inches to 6 inches of the potato plants when they are 6 inches to 8 inches tall. This provides room for the tubers to grow without exposure to sunlight. Hill again in four to six weeks to provide support for growing foliage, if necessary.