Regrowing a potato from an existing tuber is a method of gardening known as tuber propagation. This process relies on the potato’s natural ability to reproduce asexually through specialized structures. The small indentations, or “eyes,” are vegetative buds containing the genetic material necessary to sprout and develop a new plant. This allows gardeners to easily start a new crop using a single, healthy potato.
Preparing the Seed Potato
The process begins with selecting a healthy “seed potato” free from disease or blemishes. Avoid standard grocery store potatoes, as many are treated with chemical sprout inhibitors. Cut the tuber into smaller pieces, ensuring each segment weighs approximately two ounces and contains at least two healthy eyes (vegetative buds).
Cutting exposes the moist inner flesh, making it susceptible to rot and pathogens once planted. To mitigate this risk, the pieces require curing. Curing involves allowing the cut segments to sit exposed to air in a warm, moderately humid location for two to three days. During curing, the exposed surface dries out and forms a protective, leathery layer called a callus. This barrier seals the wound, preventing moisture loss and protecting the plant from decay before planting.
Selecting the Planting Environment
Potatoes require an environment that supports the expansion of subterranean tubers. The ideal medium is loose, loamy, and well-draining soil, often with a slightly acidic pH between 5.0 and 6.0. The planting site must also receive full sun, meaning at least six to eight hours of direct sunlight daily.
Gardeners can utilize traditional in-ground rows, raised beds, or large containers. After the callus has formed, plant the seed pieces cut-side down, burying them four to six inches deep. Proper spacing ensures adequate nutrient and moisture access as the plants mature. Space pieces 10 to 15 inches apart within the row, and maintain at least three feet between rows for maintenance and air circulation.
Ongoing Plant Care and Hilling
Once planted, the developing potato crop requires consistent attention to moisture levels, especially during the formation of the tubers. The soil should be kept uniformly moist but never waterlogged, as excessive saturation can lead to rot. Water requirements increase significantly when the plants begin to flower, as this signals the period of peak tuber growth beneath the soil surface.
The most unique maintenance practice for potatoes is called “hilling,” which begins once the plant foliage reaches about six to eight inches in height. Hilling involves carefully drawing up loose soil or organic material around the base of the stem. This practice is performed to protect the developing tubers from light and to encourage the formation of more tubers along the buried stem. Exposing developing tubers to sunlight causes them to turn green and produce solanine, a toxic glycoalkaloid compound that renders the potato inedible. The first mound should cover all but the top third of the foliage.
Hilling must be repeated several times throughout the growing season. As the plant grows taller, the process is repeated every two to three weeks, or whenever the new foliage reaches six to eight inches above the last mound. This continuous mounding ensures that all newly forming tubers remain deeply buried and protected until the final harvest.
Timing the Harvest and Post-Harvest Curing
The timing of the harvest depends on the desired result, distinguishing between “new potatoes” and storage potatoes. New potatoes are small, thin-skinned, and ready shortly after the plants finish flowering. For a crop intended for long-term storage, wait for the plant’s natural life cycle to conclude.
Tubers are fully mature when the above-ground foliage, or vines, naturally yellows and dies back. Once this occurs, leave the potatoes in the ground for an additional two to three weeks. This period allows the skins to thicken and “set,” reducing damage and moisture loss during harvest. Harvesting requires gentle digging several inches away from the main stem to avoid puncturing the tubers. After removal, brush clean excess soil and subject the potatoes to a final post-harvest curing process. This involves keeping them in a dark, cool, and humid environment for several days to further toughen the skin for successful storage.