When to plant Brussels sprouts in Winthrop and Twisp, WA

Start Brussels sprouts from seed indoors Feb 20 – Mar 6, then plant the young plants in the garden in Winthrop and Twisp Apr 17 – May 29.

Moderate Plant young plants (starts)

Why these dates

Winthrop and Twisp's typical last spring frost is May 15. As a cool-season crop that handles light frost, this crop can go in about 4 weeks before that.

Inland Northwest. Higher, colder interior valleys. Cold springs and an earlier fall mean a shorter season; quick-maturing varieties pay off.

Difficulty: Moderate
Sun: Full sun
Spacing: 24 inches apart
Planting depth: Plant starts at the depth they grew in the pot
Frost: Handles light frost
First harvest: About 100 days after planting

Step by step

Start seeds indoors Feb 20 – Mar 6 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.
Harden off the young plants: about a week before planting, set them outside for a few hours a day, a little longer each day.
Plant them in the garden Apr 17 – May 29, 24 inches apart. Plant starts at the depth they grew in the pot.
Water deeply once or twice a week rather than a little every day, and mulch once the soil is warm.
Harvest: Pick sprouts from the bottom of the stalk up once they're firm and about an inch across. Frost improves the flavor.

Varieties that do well here

Long Island Improved
Diablo
Churchill

Watch out for

Aphids cluster on the sprouts in late summer. Knock them off with a strong spray of water every few days.

A long-season crop picked in fall and winter, when frost sweetens the sprouts. West of the Cascades, plants keep producing well into winter.

Common questions

When is the last frost in Winthrop and Twisp, WA?

Typically May 15. In 9 years out of 10, frost is over by June 1. These are 1991–2020 NOAA climate normals for Winthrop.

Is it too late to plant Brussels sprouts in Winthrop and Twisp?

The spring planting window runs through May 29. Later plantings tend to struggle in summer heat.

When should I start Brussels sprouts from seed indoors in Winthrop and Twisp?

February 20 to March 6, which is 8 to 6 weeks before the April 17 planting date. Or buy young plants at a garden center instead.

Also plant in Winthrop and Twisp around the same time

Planting dates for Brussels sprouts in nearby areas

Wenatchee, WA Apr 1 – May 13
Omak and Okanogan, WA Apr 15 – May 27
Chelan, WA Apr 1 – May 13
Leavenworth, WA Apr 15 – May 27
Ellensburg, WA Apr 15 – May 27
Spokane, WA Apr 15 – May 27

Full planting calendar for Winthrop and Twisp · Brussels sprouts in every city