FrostCal

When to Plant Onions in Oregon

In a typical Oregon location, start seeds indoors Jan 23 – Feb 6, then transplant outdoors Mar 6 – Mar 20. Across the state, the outdoor planting window starts as early as Jan 14 in Beaverton and as late as May 12 in Altamont.

Method Start indoors, then transplant
Days to maturity 90–120 days

Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.

Onions Planting Dates by City

CityStart indoorsTransplant
PortlandDec 17 – Dec 31Jan 28 – Feb 11
EugeneJan 31 – Feb 14Mar 14 – Mar 28
SalemJan 23 – Feb 6Mar 6 – Mar 20
GreshamJan 5 – Jan 19Feb 16 – Mar 2
HillsboroFeb 5 – Feb 19Mar 19 – Apr 2
BeavertonDec 3 – Dec 17Jan 14 – Jan 28
BendMar 28 – Apr 11May 9 – May 23
MedfordJan 28 – Feb 11Mar 11 – Mar 25
SpringfieldJan 31 – Feb 14Mar 14 – Mar 28
CorvallisFeb 6 – Feb 20Mar 20 – Apr 3
AlbanyFeb 6 – Feb 20Mar 20 – Apr 3
TigardJan 21 – Feb 4Mar 4 – Mar 18
AlohaDec 3 – Dec 17Jan 14 – Jan 28
Lake OswegoJan 7 – Jan 21Feb 18 – Mar 4
KeizerJan 23 – Feb 6Mar 6 – Mar 20
Grants PassJan 28 – Feb 11Mar 11 – Mar 25
Oregon CityJan 7 – Jan 21Feb 18 – Mar 4
McMinnvilleJan 25 – Feb 8Mar 8 – Mar 22
RedmondMar 31 – Apr 14May 12 – May 26
TualatinJan 21 – Feb 4Mar 4 – Mar 18
West LinnJan 7 – Jan 21Feb 18 – Mar 4
WoodburnJan 5 – Jan 19Feb 16 – Mar 2
Forest GroveFeb 5 – Feb 19Mar 19 – Apr 2
NewbergJan 10 – Jan 24Feb 21 – Mar 7
WilsonvilleJan 7 – Jan 21Feb 18 – Mar 4
RoseburgJan 12 – Jan 26Feb 23 – Mar 9
Klamath FallsMar 31 – Apr 14May 12 – May 26
AshlandFeb 25 – Mar 11Apr 8 – Apr 22
MilwaukieDec 17 – Dec 31Jan 28 – Feb 11
BethanyFeb 5 – Feb 19Mar 19 – Apr 2

Showing the 30 most populous of 68 Oregon cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Oregon cities.

Frequently Asked Questions

When should I plant onions in Oregon?

In a typical Oregon location, start seeds indoors Jan 23 – Feb 6, then transplant outdoors Mar 6 – Mar 20. Across the state, the outdoor planting window starts as early as Jan 14 in Beaverton and as late as May 12 in Altamont.

When is the last frost in Oregon?

The average last spring frost in Oregon ranges from February 11 in Beaverton to June 9 in Altamont, based on NOAA 1991–2020 climate normals.

How long do onions take to grow?

Onions typically take 90–120 days from planting to harvest. Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.

Other Crops in Oregon

When to plant onions in other states

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