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When to Plant Soybeans in Lincoln County, WA

Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.

Lincoln County, Washington is in USDA Zone 6a. The average last spring frost is May 19 and the first fall frost is September 26, giving you a growing season of approximately 130 days.

At an elevation of 2,955 feet, Lincoln County receives approximately 21.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Soybeans during the growing season.

Lincoln County, WA (Zone 6a) Short season
130 days
Last Spring Frost May 19
130 growing days
First Fall Frost September 26

Lincoln County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 8 🍅 Harvest: Jul 31 – Sep 25
Recommended (50%) ✗ May not fit
Transplant: May 19 🍅 Harvest: Aug 11 – Oct 6
Safe Start (90%) ✗ May not fit
Transplant: Jun 16 🍅 Harvest: Sep 8 – Nov 3

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
0.7″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 700 gal / 100 sq ft
Soybeans needs ~1,525 GDD — county provides 1,982 GDD Good fit

Soybeans Planting Timeline โ€” Lincoln County, WA

Soybeans Planting Calendar

Activity When Date Range
Direct Sow May 26 May 26 โ€“ Jun 16
Harvest August 18 Aug 18 โ€“ Oct 13

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Direct Sow
June Direct Sow
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

80โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

130 days

Growing Tips for Lincoln County

Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Level Up Your Garden

Frequently Asked Questions

When should I plant Soybeans in Lincoln County, WA?

Lincoln County is in Zone 6a with an average last frost of May 19. Plan your Soybeans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lincoln County, WA?

Lincoln County, Washington is in USDA Hardiness Zone 6a. The average last spring frost is May 19 and first fall frost is September 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lincoln County gardeners in Zone 6a 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 Lincoln County, WA. Local conditions may vary. Last updated: April 2026.