Growing potatoes begins long before the seed tubers are placed into the soil. Gardeners often “wake up” the dormant potato eye through a process known as chitting or pre-sprouting, which encourages robust, early growth. This technique breaks the potato’s natural dormancy, giving the plant a significant head start on the growing season. Understanding this early preparation is the first step toward a successful and abundant potato harvest.
Is Sprouting Required for Potato Planting?
Sprouting a potato before planting is not strictly necessary, as the tuber will naturally break dormancy once placed in warm, moist soil. However, chitting is highly recommended because it provides a significant advantage to the plant’s development. Pre-sprouting accelerates the overall growing cycle, shortening the time to harvest by two to three weeks. This head start is particularly beneficial in regions with shorter growing seasons, allowing plants to mature before summer heat or early fall frost.
Chitting also contributes to a higher yield by encouraging multiple, strong sprouts on the seed potato. More sprouts translate into more main stems, which means a greater number of tubers can form beneath the soil. Planting a chitted potato ensures initial energy is directed toward immediate growth, resulting in stronger, more resilient plants.
The Process of Chitting Potatoes
Chitting encourages short, dense, and sturdy sprouts on the seed potato by controlling the environment. The process typically begins four to six weeks before the intended planting date. Tubers should be placed in a cool location with plenty of indirect light, such as a bright garage or windowsill.
The ideal temperature range for chitting is between 50°F and 60°F (10°C and 16°C). Warmer temperatures cause sprouts to grow too quickly and become weak, while colder temperatures slow the process excessively. Bright, indirect light is crucial, as this prevents the sprouts from stretching out in search of a light source, a phenomenon known as etiolation.
To set up the chitting environment, arrange the seed potatoes in a single layer using an egg carton or a shallow tray. The end containing the most “eyes” (the rose end) should face upward. Indirect light encourages the formation of short, stubby, purplish-green sprouts that are more resilient than pale, thin sprouts formed in darkness. Once the sprouts reach about one inch (2.5 cm) in length, the seed potatoes are ready for preparation.
Preparing Seed Potatoes for the Soil
Before planting, chitted seed potatoes may need to be cut to maximize yield from larger tubers. Cut only potatoes larger than an egg, ensuring each resulting piece is at least 1.25 to 2 ounces in weight. Every piece must contain at least one healthy eye or one strong, developed sprout.
After cutting, the seed pieces must undergo “curing” or “callusing” before planting. This step forms a protective layer over the cut surface, preventing rot and infection from soil-borne diseases. To cure them properly, the pieces should be left in a warm, humid, and well-ventilated location for two to four days.
The best conditions for healing involve temperatures around 55°F to 60°F (13°C to 16°C) and high humidity. This encourages the formation of a tough, leathery suberin layer. This protective barrier seals the wound, allowing the seed piece to be planted safely without risking decay in the cool, damp soil.
Planting Sprouted Potato Pieces
Planting the prepared seed pieces should be timed after the threat of hard frost has passed. The soil temperature should reach a minimum of 40°F (4°C), ideally trending toward 50°F (10°C). Seed pieces are typically planted in a trench or hole dug four to six inches deep. Ensure the sprouts are oriented to face upward when placed in the soil.
Spacing between individual seed pieces should be 10 to 12 inches apart in the row to give each plant adequate room. Rows are typically spaced 30 to 36 inches apart to allow for proper cultivation and hilling. After placing the seed pieces, cover them with only three to four inches of soil initially, leaving the trench partially unfilled.
Hilling is the practice of drawing up additional soil around the growing stems as the plant grows taller. This technique is important because new potato tubers form along the underground stem. Covering the stem encourages more tuber-producing structures to develop. Hilling also prevents developing potatoes from being exposed to sunlight, which causes them to turn green and produce a toxic compound called solanine.