Rainline Garden

When to plant onions in Olympia, WA

Plant onion sets in Olympia Mar 18 – Apr 22.

Moderate Plant small onion bulbs (sets)

Why these dates

Olympia's typical last spring frost is April 29. As a cool-season crop that handles light frost, this crop can go in about 6 weeks before that.

West-side valleys. The Willamette Valley, Puget Sound and southern Oregon valleys. Long frost-free seasons, but soil stays cold and wet into May, so warm crops wait for warm soil, not just the last frost.

Difficulty
Moderate
Sun
Full sun
Spacing
4 inches apart
Planting depth
Sets 1 inch deep, tip just showing
Frost
Handles light frost
First harvest
About 110 days after planting

Step by step

  1. Prepare the bed: loosen the soil and mix in an inch or two of compost.
  2. Plant onion sets Mar 18 – Apr 22, 4 inches apart, sets 1 inch deep, tip just showing.
  3. Water regularly and keep the bed weeded; onions don't compete well.
  4. Harvest: When the tops flop over in late summer, pull the onions and let them dry in a shady, airy spot for two weeks.

Varieties that do well here

  • Walla Walla Sweet
  • Copra (stores well)
  • Redwing

Watch out for

Weeds outcompete onions' thin leaves. Keep the bed weeded and mulched.

Plant as soon as the soil is dry enough to work. Pick long-day varieties for the Northwest.

Common questions

When is the last frost in Olympia, WA?

Typically April 29. In 9 years out of 10, frost is over by May 15. These are 1991–2020 NOAA climate normals for Olympia Airport.

Is it too late to plant onions in Olympia?

The spring planting window runs through April 22. Later plantings tend to struggle in summer heat.

How long until I can harvest onions?

About 110 days after planting. When the tops flop over in late summer, pull the onions and let them dry in a shady, airy spot for two weeks.

Also plant in Olympia around the same time

Planting dates for onions in nearby areas

Full planting calendar for Olympia · Onions in every city