When to plant Brussels sprouts in The Dalles, OR

Start Brussels sprouts from seed indoors Feb 4–18, then plant the young plants in the garden in The Dalles Apr 1 – May 13.

Moderate Plant young plants (starts)

Why these dates

The Dalles's typical last spring frost is April 11. As a cool-season crop that handles light frost, this crop doesn't need to wait for that date. In the Columbia Basin and low eastern valleys, though, the soil usually isn't ready to work until about April 1.

Columbia Basin and low eastern valleys. Hot, dry summers and quick spring warm-up. Warm crops go in earlier than west of the Cascades, and irrigation matters more than rain.

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 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.
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 1 – May 13, 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 The Dalles, OR?

Typically April 11. In 9 years out of 10, frost is over by April 28. These are 1991–2020 NOAA climate normals for The Dalles Municipal Airport (Dallesport, WA).

Is it too late to plant Brussels sprouts in The Dalles?

The spring planting window runs through May 13. Later plantings tend to struggle in summer heat.

When should I start Brussels sprouts from seed indoors in The Dalles?

February 4 to February 18, which is 8 to 6 weeks before the April 1 planting date. Or buy young plants at a garden center instead.