When to plant arugula in Seattle and Tacoma, WA

Plant arugula from seed, directly in the garden in Seattle and Tacoma, Mar 1 – Apr 12. For a fall harvest, plant again Aug 27 – Sep 17.

Easy Plant seeds in the ground

Why these dates

Seattle and Tacoma's typical last spring frost is March 2. As a cool-season crop that handles light frost, this crop doesn't need to wait for that date. In the west-side valleys, though, the soil usually isn't ready to work until about March 1.

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: Easy
Sun: Full sun to part shade
Spacing: Thin to 4 inches apart
Planting depth: ¼ inch deep
Frost: Handles light frost
First harvest: About 35 days after planting

Step by step

Prepare the bed: loosen the soil and mix in an inch or two of compost.
Plant seeds Mar 1 – Apr 12, ¼ inch deep, Thin to 4 inches apart.
Keep the soil evenly moist until sprouts appear, which can take one to three weeks in cool soil.
Plant again Aug 27 – Sep 17 for a fall harvest.
Harvest: Pick leaves when they're 2 to 3 inches long, about three weeks after sowing. Young leaves are the mildest.

Varieties that do well here

Astro
Wild arugula (Sylvetta)
Rocket

Watch out for

Flea beetles riddle the leaves with tiny holes in spring. Floating row cover laid on at sowing keeps them off.

Fast and frost-tolerant. It bolts in heat, so sow small batches in spring and again in late summer.

Common questions

When is the last frost in Seattle and Tacoma, WA?

Typically March 2. In 9 years out of 10, frost is over by March 23. These are 1991–2020 NOAA climate normals for Seattle-Tacoma International Airport.

Is it too late to plant arugula in Seattle and Tacoma?

The spring planting window runs through April 12. If you miss it, plant again for fall from August 27 to September 17.

How long until I can harvest arugula?

About 35 days after planting. Pick leaves when they're 2 to 3 inches long, about three weeks after sowing. Young leaves are the mildest.