Description Start seed indoors as early as you can as the bigger the transplant, the better the mature onion will be. Walla Walla withstands considerable cold, so if possible, you can start seed in a cold-frame to get a jump on the season. Yellow fleshed super sweet onion. Size of harvested bulb is variable from 5-15 cm (2-6″). This is not a long-term storage onion so enjoy them fresh. How to Grow Seed can be started indoors in a soil-less growing medium in February. The seedlings can then be transplanted outside later in spring. Seed can also be sown directly outdoors from mid April, 8-15 mm (1/4-1/2″) deep and 15 mm (1/2″) apart in rows 30 cm (12″) apart. Thin seedlings to 12.5 cm (5″) apart. Onions do best in a sunny site with fertile, well drained soil. Bend over any flower stalks that start to grow so the plant’s energy goes into building the bulb. One packet sows approximately 6 m (20’) of row.
