Rainline Garden

When to plant leeks in Portland, OR

Start leeks from seed indoors Jan 4–18, then plant the young plants in the garden in Portland Mar 15 – Apr 26.

Easy Plant young plants (starts)

Why these dates

Portland's typical last spring frost is March 13. In the west-side valleys, the soil is usually ready for leeks around March 15.

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
Spacing
6 inches apart
Planting depth
Set seedlings in a hole about 6 inches deep so the stems grow long and white
Frost
Handles light frost
First harvest
About 120 days after planting

Step by step

  1. Start seeds indoors Jan 4–18 in trays or small pots under a grow light or in your sunniest window. Or skip this step and buy young plants (starts) at a garden center.
  2. Harden off the young plants: about a week before planting, set them outside for a few hours a day, a little longer each day.
  3. Plant them in the garden Mar 15 – Apr 26, 6 inches apart. Set seedlings in a hole about 6 inches deep so the stems grow long and white.
  4. Water deeply once or twice a week rather than a little every day, and mulch once the soil is warm.
  5. Harvest: Dig whenever stems are an inch or more across. West of the Cascades you can leave them in the ground and harvest all winter.

Varieties that do well here

  • King Richard (early)
  • Bandit (winter-hardy)
  • American Flag

Watch out for

Weeds crowd young leeks. Mulch and weed regularly while the plants are small.

Slow but nearly foolproof. West of the Cascades they stand in the garden all winter, ready to dig as you need them.

Common questions

When is the last frost in Portland, OR?

Typically March 13. In 9 years out of 10, frost is over by April 1. These are 1991–2020 NOAA climate normals for Portland International Airport.

Is it too late to plant leeks in Portland?

The spring planting window runs through April 26. Later plantings tend to struggle in summer heat.

When should I start leeks from seed indoors in Portland?

January 4 to January 18, which is 10 to 8 weeks before the March 15 planting date. Or buy young plants at a garden center instead.

Also plant in Portland around the same time

Planting dates for leeks in nearby areas

Full planting calendar for Portland · Leeks in every city