The Walla Walla onion is a sweet white onion identified with the Pacific Northwest and the Walla Walla, Washington, area in particular. The onion is a bulb onion bred for use as a diced or sliced product rather than for use fresh as a green onion or as a small bulb for pickling. Onions are commonly harvested in the summer or early fall of the year.
Harvest Walla Walla onions when the tops fall over. This indicates the plant is no longer actively growing. Lift the onions out of the soil using a garden fork or shovel. Leave the onion laying in the garden with the top attached for about two weeks. Remove the onion from the garden when the skin resembles paper.
Harvest commonly occurs about four months after the Walla Walla onion sets were planted in the garden. In Washington and Oregon, the Walla Walla and some other onion varieties are planted in the fall and allowed to overwinter in the ground. The plants begin growth the next spring and are ready for harvest in the summer.
Trimming the Onion
Trim the onion when it is removed from the garden. Clip the onion top off about 2 inches above the bulb. The onion stems can be composted.
Storing the Onion
Place the onions in a mesh or burlap bag for storage. These types of bags allow air circulation all around the onion. Hang the bags to further promote air circulation and avoid damp spots in the bag from contact with a floor. Store onions in conditions above freezing but below 40 degrees Fahrenheit for best long-term storage.