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A row of leeks growing in a field
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When to plant leeks in Hillsboro and Beaverton, OR

Start leeks from seed indoors Jan 8–22, then plant the young plants in the garden in Hillsboro and Beaverton Mar 19 – Apr 30.

Easy Plant young plants (starts)

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

Why these dates

Hillsboro and Beaverton's typical last spring frost is April 16. As a cool-season crop that handles light frost, this crop can go in about 4 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.

How to grow leeks in Hillsboro and Beaverton

  1. Start seeds indoors Jan 8–22 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 19 – Apr 30, 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.

Key numbers

Growing notes

What makes the difference in Northwest gardens, in plain language.

Soil and feeding

Leeks like deep, loose, fertile soil with a pH of about 6.0 to 7.5. They are heavy feeders over a long season, so work in compost before planting and side-dress with nitrogen a couple of times through summer. Their roots are shallow and their leaves don't shade out weeds, so keep the bed weeded and mulched. Even moisture matters: dry spells slow growth and make stems tough.

Growing long, white stems

The white part of a leek is simply stem that grew in the dark. Setting seedlings in a 6-inch-deep hole, as the guide describes, starts the process. Don't fill the hole; water settles soil around the plant over time. As leeks grow, you can hill soil or mulch up around the stems for more white length. Keep soil out of the leaf folds, where it is hard to wash out. King Richard is a quick summer and fall leek, while Bandit and American Flag hold up through winter.

Winter harvest and problems

West of the Cascades, hardy leeks stand in the garden all winter and can be dug as needed, which makes them one of the best winter vegetables in the region. East of the Cascades, harsh cold may damage them, so harvest before the deep freeze or cover them heavily with straw. Rust, small orange spots on the leaves, sometimes appears in late summer. It looks bad but rarely ruins the stems; pick off affected leaves and give plants more space. Onion thrips can silver the leaves in hot, dry eastern summers.

Common questions

When is the last frost in Hillsboro and Beaverton, OR?

Typically April 16. In 9 years out of 10, frost is over by May 3. These are 1991–2020 NOAA climate normals for Portland-Hillsboro Airport.

Is it too late to plant leeks in Hillsboro and Beaverton?

The spring planting window runs through April 30. Later plantings tend to struggle in summer heat.

When should I start leeks from seed indoors in Hillsboro and Beaverton?

January 8 to January 22, which is 10 to 8 weeks before the March 19 planting date. Or buy young plants at a garden center instead.

How do I get long white leeks?

Plant seedlings deep, in holes about 6 inches deep, and hill soil or mulch around the stems as they grow. The part kept from light stays white and tender. Rich soil and steady water help them grow thick.

Can I leave leeks in the ground over winter?

West of the Cascades, yes: winter-hardy varieties like Bandit can be dug all winter. East of the Cascades, mulch them heavily or harvest before hard freezes. Dig them before they send up flower stalks in spring.

What are the orange spots on my leek leaves?

That's rust, a fungal disease common in late summer. It's mostly cosmetic and the stems are still good to eat. Remove the worst leaves, avoid crowding, and don't plant leeks or garlic in the same spot next year.

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Planting dates for leeks in nearby areas

Full planting calendar for Hillsboro and Beaverton · Leeks in every city