Try to aim for a seed spacing of at least
1.95 inches (5.0 cm) and sow at a depth of around
0.98 inches (2.5 cm). Soil temperature should be kept higher than
13°C / 55°F to ensure good germination.
By our calculations, you should look at sowing Walla Walla Sweet about 28 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Walla Walla Sweet is a very hardy plant.
The Walla Walla sweet onion is named for Walla Walla county (Washington, USA) where the variety originated in the early 1900’s.