Chitting is the practice of pre-sprouting seed potatoes before planting to encourage the development of robust, short shoots. This process gives the potato plant a head start in the growing season, potentially leading to an earlier and more substantial harvest. Proper storage during this phase is important to ensure the resulting sprouts are strong and healthy. Unlike potatoes stored for consumption, seed potatoes require specific environmental conditions to control sprout growth.
Preparing Seed Potatoes Before Storage
Before initiating the chitting process, seed potatoes require thorough preparation to maximize their viability. Carefully inspect each tuber, setting aside any that show signs of disease, mold, or soft spots, as these compromised potatoes can spread pathogens to healthy stock. Using certified seed potatoes also minimizes the risk of introducing common potato diseases into the garden.
If a seed potato is larger than a standard egg, cut it into smaller pieces. Each section should weigh approximately 1.5 to 2 ounces and contain at least one or two “eyes,” the indentations from which sprouts emerge. The newly cut surfaces must then be allowed to cure, forming a protective, cork-like layer called suberin. Achieve this healing by holding the pieces in a warm environment, ideally between 50 to 55°F (10 to 13°C), with high humidity for two to seven days. This layer minimizes moisture loss and prevents the entry of rot-causing organisms before planting.
Establishing Ideal Storage Conditions
Once the seed potatoes are prepared, establishing the correct environment is necessary to encourage the development of strong, “green sprouts.” The storage temperature should be cool yet reliably above freezing, ideally maintained between 40 and 50°F (4 and 10°C). Temperatures above this range accelerate sprouting too quickly, resulting in spindly growth, while temperatures near freezing risk damaging the tuber cells. This controlled temperature slows the potato’s metabolism while still allowing for sprout initiation.
Light exposure is a defining characteristic of the chitting process. Seed potatoes should be exposed to bright, indirect light, such as near a window or under supplemental lighting. Constant light prevents the production of etiolated sprouts, which are long, white, and brittle. Instead, it promotes the formation of short, stocky, dark green or purplish shoots. To achieve this, arrange the tubers in a single layer, typically in shallow trays or egg cartons, with the end containing the most eyes facing upward.
Adequate ventilation is required to manage the potato’s natural respiration process, which releases carbon dioxide and moisture. Good airflow prevents the buildup of these gases and reduces the risk of fungal and bacterial growth. Maintaining a moderate to high relative humidity, around 85 to 90 percent, is equally important to minimize water loss from the tuber. This prevents shriveling and helps keep the seed piece firm and viable until planting.
Monitoring and Addressing Storage Issues
Regular monitoring of the stored seed potatoes is necessary to maintain their health and manage any issues that arise. Check the tubers every few days for signs of decay, such as soft spots, mold, or an unpleasant odor, which often indicates bacterial soft rot. Any affected potato must be removed immediately to prevent the spread of pathogens to the rest of the healthy stock.
If sprouts grow excessively long, pale, and fragile, the storage environment is likely too warm or lacks sufficient light. Lower the temperature or increase the light source to promote sturdier growth. If the sprouts are already several inches long, they can be carefully rubbed off the potato. This forces the tuber to restart sprouting, which consumes additional energy but ensures the new shoots will be short and robust for planting. The ideal storage duration is typically four to six weeks, allowing sprouts to reach the optimal planting length of about a half-inch to one inch.