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When to Plant Asparagus in Lewis County, WA

Asparagus is a long-lived perennial vegetable that produces tender spears each spring for 15-20 years once established. It requires patience but rewards with reliable harvests.

Lewis County, Washington is in USDA Zone 7b. The average last spring frost is April 25 and the first fall frost is October 24, giving you a growing season of approximately 182 days.

At an elevation of 327 feet, Lewis County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Asparagus during the growing season.

Lewis County, WA (Zone 7b) Moderate season
182 days
Last Spring Frost April 25
182 growing days
First Fall Frost October 24

Lewis County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Apr 27
Recommended (50%) ✓ Fits season
Transplant: May 9
Safe Start (90%) ✓ Fits season
Transplant: Jul 8

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 226 gal / 100 sq ft
Asparagus needs ~13,231 GDD — county provides 2,639 GDD May not mature

Asparagus Planting Timeline โ€” Lewis County, WA

Asparagus Planting Calendar

Activity When Date Range
Transplant Outdoors May 9 May 9 โ€“ May 23

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June โ€”
July โ€”
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

730โ€“1095 days

Soil pH

6.5 โ€“ 7.5

USDA Zone

Zone 7b

Growing Season

182 days

Growing Tips for Lewis County

Plant crowns in deep trenches with compost. Do not harvest spears for the first two years to allow root establishment. Mulch heavily to suppress weeds and retain moisture.

Companion Planting

Good Companions

Avoid Planting Near

  • Garlic
  • Onion

Level Up Your Garden

Frequently Asked Questions

When should I plant Asparagus in Lewis County, WA?

Lewis County is in Zone 7b with an average last frost of April 25. Plan your Asparagus planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lewis County, WA?

Lewis County, Washington is in USDA Hardiness Zone 7b. The average last spring frost is April 25 and first fall frost is October 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lewis County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Lewis County, WA. Local conditions may vary. Last updated: April 2026.