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When to Plant Edamame in Okanogan County, WA

Edamame are soybeans harvested at the immature green stage for a sweet, nutty snack. They are high in protein and easy to grow in warm climates.

Okanogan County, Washington is in USDA Zone 5b. The average last spring frost is May 13 and the first fall frost is September 26, giving you a growing season of approximately 136 days.

At an elevation of 3,788 feet, Okanogan County receives approximately 21.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Edamame to ensure they mature before fall.

Okanogan County, WA (Zone 5b) Short season
136 days
Last Spring Frost May 13
136 growing days
First Fall Frost September 26

Okanogan County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (12 days to spare)
Transplant: May 8 🍅 Harvest: Jul 24 – Sep 4
Recommended (50%) ✓ Fits season (17 days to spare)
Transplant: May 13 🍅 Harvest: Jul 29 – Sep 9
Safe Start (90%) ✓ Fits season (13 days to spare)
Transplant: Jun 6 🍅 Harvest: Aug 22 – Oct 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 777 gal / 100 sq ft
Edamame needs ~1,072 GDD — county provides 1,666 GDD Excellent fit

Edamame Planting Timeline โ€” Okanogan County, WA

Edamame Planting Calendar

Activity When Date Range
Direct Sow May 20 May 20 โ€“ Jun 10
Harvest August 5 Aug 5 โ€“ Sep 16

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 โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

75โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5b

Growing Season

136 days

Growing Tips for Okanogan County

Direct sow after soil is warm. Do not over-fertilize with nitrogen. Harvest when pods are plump and bright green but before they start to yellow. Steam or boil pods before eating.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

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Frequently Asked Questions

When should I plant Edamame in Okanogan County, WA?

Okanogan County is in Zone 5b with an average last frost of May 13. Plan your Edamame planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Okanogan County, WA?

Okanogan County, Washington is in USDA Hardiness Zone 5b. The average last spring frost is May 13 and first fall frost is September 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Okanogan County gardeners in Zone 5b 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 Okanogan County, WA. Local conditions may vary. Last updated: April 2026.