This is the classic large overwintering onion of the Pacific Northwest. A very large, juicy onion with a mild sweet flavour. It can be planted in the spring if given a really early start indoors, or in August to overwinter. Spring planted Walla Walla sweet onion seeds result in bulbs that are not quite as mild as the overwintered ones and may not size up as well. Plants can also be harvested as a delicious, sweet bunching onion.This variety is hardy to -23°C (-10°F). It is most definitely a long day onion, suitable for planting between the 35th and 55th parallels. It might not have good storage ability, but it makes beautiful, caramelized onions!
Matures in 125 days, spring sown - 300 days fall sown
West Coast Seeds Walla Walla Onions Seeds, Per Package
Starting
Transplants are preferred for home gardeners. Sow 3 seeds 5mm-1cm (¼-½”) deep in each cell of a 72-cell tray. Transplant as a clump, spacing each 15cm (6″) apart in rows 45-75cm (18-30″) apart. Scallions can be spaced at 2-5cm (1-2″) apart in rows 15cm (6″) apart.
Timing
Start shallots and storage onions indoors in late winter and early spring, and transplant 2-4 weeks after the last frost date. Overwintering onions need to be started in early summer, and transplanted by the middle of August. Scallions can be direct sown every 3 weeks from two weeks after the last frost date to late summer. Optimal soil temperature for germination: 21-25°C (70-75°F). Seeds will emerge in 6-12 days, depending on conditions.
Harvest
Stop watering in the beginning of August to mature the bulbs in dry soil. After half the tops have fallen, push over the remainder, wait a week and lift the bulbs. Curing is essential for long storage: Spread bulbs out in a single layer in an airy spot out of direct sunlight. Once no more green is visible on any of the leaves, and they are dry and crisp, the onion is cured. If weather is poor, cure indoors. Storage: Keep onions in mesh sacks or hang in braids so they get good ventilation, and hang sacks where air is dry and very cool, but not freezing. Check them regularly and remove any sprouting or rotting onions. Well-cured storage onions should keep until late spring.
