When to Plant Onions in Oregon
In Oregon, the time to plant onions outside runs from Jan 24 – Feb 7 in Coos Bay to May 12 – May 26 in Redmond. In Portland, it's Jan 28 – Feb 11. The average last spring frost differs by about 15 weeks across the state (Feb 21 in Coos Bay, Jun 9 in Redmond), so use the dates for the town nearest you.
Onions are cold-hardy. Plant sets or transplants early so they grow leaves before long summer days trigger bulbing.
- Start indoors: 10–12 weeks before the last frost.
- Plant outside: 2–4 weeks before the last frost.
Onions planting dates in Oregon by city
| City | Zone | Start indoors | Plant outside |
|---|---|---|---|
| Albany | 8b | Jan 23 – Feb 6 | Mar 20 – Apr 3 |
| Ashland | 8a | Feb 11 – Feb 25 | Apr 8 – Apr 22 |
| Beaverton | 9a | Jan 7 – Jan 21 | Mar 4 – Mar 18 |
| Bend | 6b | Mar 14 – Mar 28 | May 9 – May 23 |
| Canby | 8b | Dec 24 – Jan 7 | Feb 18 – Mar 4 |
| Central Point | 8b | Jan 14 – Jan 28 | Mar 11 – Mar 25 |
| Coos Bay | 9a | Nov 29 – Dec 13 | Jan 24 – Feb 7 |
| Cornelius | 8b | Jan 22 – Feb 5 | Mar 19 – Apr 2 |
| Corvallis | 8b | Jan 23 – Feb 6 | Mar 20 – Apr 3 |
| Dallas | 8b | Jan 22 – Feb 5 | Mar 19 – Apr 2 |
| Eugene | 8b | Jan 17 – Jan 31 | Mar 14 – Mar 28 |
| Forest Grove | 8b | Jan 22 – Feb 5 | Mar 19 – Apr 2 |
| Grants Pass | 8b | Jan 14 – Jan 28 | Mar 11 – Mar 25 |
| Gresham | 9a | Dec 22 – Jan 5 | Feb 16 – Mar 2 |
| Happy Valley | 8b | Dec 24 – Jan 7 | Feb 18 – Mar 4 |
| Hermiston | 7b | Feb 1 – Feb 15 | Mar 29 – Apr 12 |
| Hillsboro | 8b | Jan 22 – Feb 5 | Mar 19 – Apr 2 |
| Keizer | 8b | Jan 9 – Jan 23 | Mar 6 – Mar 20 |
| Klamath Falls | 6b | Mar 17 – Mar 31 | May 12 – May 26 |
| Lake Oswego | 9a | Dec 24 – Jan 7 | Feb 18 – Mar 4 |
| Lebanon | 8b | Dec 20 – Jan 3 | Feb 14 – Feb 28 |
| McMinnville | 8b | Jan 11 – Jan 25 | Mar 8 – Mar 22 |
| Medford | 8b | Jan 14 – Jan 28 | Mar 11 – Mar 25 |
| Milwaukie | 9a | Dec 3 – Dec 17 | Jan 28 – Feb 11 |
| Newberg | 8b | Dec 27 – Jan 10 | Feb 21 – Mar 7 |
| Oregon City | 9a | Dec 24 – Jan 7 | Feb 18 – Mar 4 |
| Pendleton | 7a | Jan 28 – Feb 11 | Mar 25 – Apr 8 |
| Portland | 8b | Dec 3 – Dec 17 | Jan 28 – Feb 11 |
| Redmond | 6b | Mar 17 – Mar 31 | May 12 – May 26 |
| Roseburg | 8b | Dec 29 – Jan 12 | Feb 23 – Mar 9 |
| Salem | 8b | Jan 9 – Jan 23 | Mar 6 – Mar 20 |
| Sherwood | 8b | Dec 27 – Jan 10 | Feb 21 – Mar 7 |
| Springfield | 8b | Jan 17 – Jan 31 | Mar 14 – Mar 28 |
| The Dalles | 8a | Jan 17 – Jan 31 | Mar 14 – Mar 28 |
| Tigard | 9a | Jan 7 – Jan 21 | Mar 4 – Mar 18 |
| Troutdale | 9a | Jan 1 – Jan 15 | Feb 26 – Mar 12 |
| Tualatin | 9a | Jan 7 – Jan 21 | Mar 4 – Mar 18 |
| West Linn | 9a | Dec 24 – Jan 7 | Feb 18 – Mar 4 |
| Wilsonville | 8b | Dec 24 – Jan 7 | Feb 18 – Mar 4 |
| Woodburn | 8b | Dec 22 – Jan 5 | Feb 16 – Mar 2 |
Calculated from each town's average (50%) frost dates, from the nearest NOAA station (1991–2020). Typical dates for the 2027 planting season, based on NOAA's 1991–2020 averages. They are long-term odds, not a forecast: always check your local forecast before planting. Zones: 2023 USDA Plant Hardiness Zone Map (USDA-ARS and Oregon State University). Not the official map; see planthardiness.ars.usda.gov.
See all frost dates in Oregon, or the general guide to when to plant onions.
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