Rainline Garden

When to plant Brussels sprouts in Walla Walla, WA

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

Moderate Plant young plants (starts)

Why these dates

Walla Walla's typical last spring frost is March 27. In the Columbia Basin and low eastern valleys, the soil is usually ready for Brussels sprouts around 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

  1. 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.
  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 Apr 1 – May 13, 24 inches apart. Plant starts at the depth they grew in the pot.
  4. Water deeply once or twice a week rather than a little every day, and mulch once the soil is warm.
  5. 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 Walla Walla, WA?

Typically March 27. In 9 years out of 10, frost is over by April 22. These are 1991–2020 NOAA climate normals for Walla Walla Regional Airport.

Is it too late to plant Brussels sprouts in Walla Walla?

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 Walla Walla?

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.

Also plant in Walla Walla around the same time

Planting dates for Brussels sprouts in nearby areas

Full planting calendar for Walla Walla · Brussels sprouts in every city