Encouraging a potato to sprout before planting is known as chitting, or pre-sprouting. This technique accelerates the potato’s natural growth cycle, giving gardeners a head start on the season. Chitting leads to earlier harvests and potentially higher yields. Developing robust sprouts indoors allows the potato plant to establish itself more quickly once planted.
Selecting and Preparing Seed Potatoes
Rapid sprouting begins with selecting quality, certified seed potatoes, which are guaranteed to be disease-free. Certified stock is important because grocery store potatoes are often treated with a growth inhibitor to prevent sprouting. Potatoes larger than an egg can be cut into pieces, but each segment must contain at least two to three healthy “eyes,” the dormant buds where sprouts will emerge.
After cutting, the pieces must be cured for two to three days in a warm, dry, and well-ventilated location away from direct sunlight. This curing process allows the cut surface to dry out and form a protective, leathery callus. The callus acts as a seal, preventing the potato from rotting once planted and ensuring the tuber’s energy focuses on sprout development.
Optimizing Environmental Conditions
The speed and quality of sprouting are controlled by manipulating the surrounding environment. For best results, place the seed potatoes upright in trays or egg cartons, ensuring the end with the most eyes, known as the “rose end,” faces upward. The ideal temperature range for rapid chitting is consistently between 50 and 70 degrees Fahrenheit (10–21°C).
Maintaining a steady temperature signals to the potato that the growing season has begun. The tubers must also be exposed to bright, indirect light, such as a sunny windowsill. Light exposure is necessary to produce short, sturdy, purple or green sprouts, which are more robust than the long, pale sprouts that develop in darkness. These compact sprouts are less likely to break off during planting and give the young plant a stronger initial start.
Kickstarting Slow Sprouting
If seed potatoes are reluctant to break dormancy, a short, intense period of warmth and humidity can initiate the process. One method involves creating a temporary “sweating” environment by placing the tubers in a dark, humid space, such as a paper bag with a damp cloth, for 24 to 48 hours. The sudden shift to high heat and moisture overrides dormancy signals, forcing the eyes to swell.
Alternatively, placing the potatoes near a temporary heat source, like a seedling heat mat, provides the sudden temperature spike needed to trigger growth by accelerating the metabolic rate. Another technique is to place the potatoes in a closed container with ripening fruit, such as apples or bananas. The ethylene gas released by the fruit acts as a natural hormone, signaling the potato to begin sprouting. After using any of these kickstarting methods, the potatoes must be returned to the optimal cool, bright, and airy environment to ensure the new sprouts remain short and strong.