Walla Walla Sweet Onion is the famous mild yellow variety that put Walla Walla, Washington on the culinary map. This open-pollinated cultivar produces large, sweet bulbs that have become synonymous with Pacific Northwest agriculture. Maturing in 125 days from transplants, these onions develop their legendary mild flavor in the volcanic soils of their namesake region, where cool springs allow sugars to develop without the sharp bite typical of storage onions.
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The legendary sweetness of Walla Walla onions comes from the unique growing conditions of eastern Washington, where cool springs and well-drained soils create the perfect environment for sugar development. Unlike storage onions bred for pungency and keeping quality, Walla Walla Sweets are meant to be enjoyed fresh, celebrated for their mild flavor that can be eaten raw like an apple. This yellow variety has become so culturally significant that it's protected by federal marketing orders, ensuring only onions grown in designated areas can carry the Walla Walla name.
These sweet onions excel in fresh applications where their mild flavor can shine through without cooking. They're perfect for raw preparations like salads, salsas, and sandwiches, or can be caramelized to bring out their natural sugars in soups, gratins, and roasted dishes.
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In long and intermediate-day areas, sow seeds indoors 6 to 8 weeks before your last frost date. Use 128-cell trays with one seed per cell, covering seeds with 1/4 inch of soil.
Transplant seedlings outdoors after hardening off, spacing them 4 inches apart in rows 12 to 18 inches apart. Unruly tops may be clipped to 5 inches at transplant time to help establishment.
Harvest when bulbs have reached full size and the tops begin to yellow and fall over, typically 125 days from transplanting. Cure in a warm, dry, well-ventilated area until the outer skins are papery and the necks are completely dry.
Clip unruly tops to 5 inches at transplant time if needed to help establishment, but avoid excessive pruning that might stress the plants.
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“This variety originated in the Walla Walla Valley of Washington State, where it became the region's signature agricultural product. The famous mild character developed through generations of selection in the area's unique terroir of volcanic soils and specific climate conditions that favor sugar development over pungency.”