Onions are a staple crop in central Appalachia. Before the popular green bunching scallions and bulb onion, multiplier onions were widely grown in gardens throughout West Virginia.
Multiplier onions are often called potato onions or shallots. Unlike traditional onions, multiplier onions produce clusters around a central bulb. As a result, the yield from multiplier onions is much greater than traditional bulb onions.
Although onions are biennial, meaning they produce seeds the second year, multiplier onions, such as potato onions, rarely produce seeds. Instead, the small bulbs in the cluster are saved for planting the following year.
Potato onions are typically white or yellow bulb onions, which have a mild flavor and are used for cooking. Each potato onion “hill” or cluster will typically produce six to 11 bulbs.
Potato onions can be planted in the fall or early spring but are traditionally overwintered as a “winter onion” in Appalachia. The potato onion can tolerate sub-freezing temperatures. The bulbs are planted in fall (early November) in West Virginia.
Potato onions are excellent plants for containers or raised beds. The onion bulbs or “sets” are planted approximately 6 inches apart within the row and 18 to 24 inches between rows.
In some regions of West Virginia, the onions will produce green bunching onions for harvest in early winter. Otherwise, the onion can be harvested as green bunching onions in spring or allowed to mature to full-sized bulbs for harvest in early summer.
After harvest, the potato onions can be cured in a warm, dry place for about a month and stored in a cool, dry environment for the remainder of the year. Be sure to save bulbs from vigorous hills for planting later in the year.
By Lewis W. Jett, WVU Extension Specialist – Commercial Horticulture