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When to Plant Soybeans in Dewey County, OK

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.

Dewey County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 13 and the first fall frost is October 24, giving you a growing season of approximately 194 days.

At an elevation of 745 feet, Dewey County receives approximately 28.5 inches of rainfall annually with predominantly loam soil. Summer highs average 93ยฐF, providing good warmth for Soybeans during the growing season.

Dewey County, OK (Zone 7a) Moderate season
194 days
Last Spring Frost April 13
194 growing days
First Fall Frost October 24

Dewey County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (55 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 29 – Aug 24
Recommended (50%) ✓ Fits season (54 days to spare)
Transplant: Apr 13 🍅 Harvest: Jul 6 – Aug 31
Safe Start (90%) ✓ Fits season (54 days to spare)
Transplant: Apr 29 🍅 Harvest: Jul 22 – Sep 16

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
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 794 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Soybeans needs ~1,975 GDD — county provides 3,831 GDD Excellent fit

Soybeans Planting Timeline โ€” Dewey County, OK

Soybeans Planting Calendar

Activity When Date Range
Direct Sow April 20 Apr 20 โ€“ May 11
Harvest July 13 Jul 13 โ€“ Sep 7

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Direct Sow
May Direct Sow
June โ€”
July Harvest
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

80โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7a

Growing Season

194 days

Growing Tips for Dewey 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 Dewey County, OK?

Dewey County is in Zone 7a with an average last frost of April 13. Plan your Soybeans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Dewey County, OK?

Dewey County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 13 and first fall frost is October 24.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Dewey County gardeners in Zone 7a 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 Dewey County, OK. Local conditions may vary. Last updated: April 2026.