Oregon planting dates for onions
Dates for Oregon vary significantly by region. Use the average frost date lookup for your specific ZIP code, then apply the standard offsets: start onions indoors 12 weeks before your last frost; transplant 2 weeks before last frost;
Why these dates
Onions are day-length sensitive. Long-day varieties for the North (above latitude 35), short-day varieties for the South (below 35), day-neutral varieties work anywhere.
The dates above are anchored to Oregon's average last spring frost date of 04-15 (W) to 05-25 (E), with offsets standard across university Extension publications. For zone-specific local timing, use the frost date lookup tool with your ZIP code.
More on growing onions
The full growing guide for onions - varieties, soil, fertilization, pests, harvest, storage - is here: Onions growing guide.
More Oregon planting information
- Full Oregon planting calendar (all crops + ornamentals)
- Find your exact USDA zone by ZIP
- Look up your average frost dates
- Seed starting timeline calculator