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Fresh green asparagus spears close up
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When to plant asparagus in Sunnyside, Grandview and Prosser, WA

Plant asparagus crowns in Sunnyside, Grandview and Prosser Apr 3 – May 15.

Moderate Plant dormant crowns

Why these dates

Sunnyside, Grandview and Prosser's typical last spring frost is May 1. As a hardy perennial, this crop can go in about 4 weeks before that.

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
12 to 18 inches apart
Planting depth
In a trench 6 to 8 inches deep, covered gradually as the spears grow
Frost
Hardy perennial; comes back every year
First harvest
Light picking in year two; full harvests from year three

Step by step

  1. Pick a sunny spot with soil that drains well, and mix in an inch or two of compost.
  2. Plant asparagus crowns Apr 3 – May 15, 12 to 18 inches apart. In a trench 6 to 8 inches deep, covered gradually as the spears grow.
  3. Fill the trench in gradually as the shoots grow. Keep the bed weeded, and cut the ferns down only after they turn brown in fall.
  4. Harvest: Snap spears at soil level when they're 6 to 8 inches tall. Stop picking when new spears are pencil-thin, and let the ferns grow.

Varieties that do well here

  • Jersey Knight
  • Millennium
  • Purple Passion

Watch out for

Asparagus beetles chew the spears and ferns. Hand-pick them in the morning.

A bed that produces for 15 to 20 years. Don't harvest the first year, pick lightly the second, then fully from year three.

Common questions

When is the last frost in Sunnyside, Grandview and Prosser, WA?

Typically May 1. In 9 years out of 10, frost is over by May 18. These are 1991–2020 NOAA climate normals for Sunnyside.

Is it too late to plant asparagus in Sunnyside, Grandview and Prosser?

The spring planting window runs through May 15. Potted plants can still go in later if you water them faithfully through their first summer.

How long until I can pick asparagus?

Light picking in year two; full harvests from year three. Snap spears at soil level when they're 6 to 8 inches tall. Stop picking when new spears are pencil-thin, and let the ferns grow.

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Planting dates for asparagus in nearby areas

Full planting calendar for Sunnyside, Grandview and Prosser · Asparagus in every city