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When to Plant Soybeans in Blaine 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.

Blaine County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 27, giving you a growing season of approximately 200 days.

At an elevation of 719 feet, Blaine County receives approximately 30.2 inches of rainfall annually with predominantly loam soil. Summer highs average 90ยฐF, providing good warmth for Soybeans during the growing season.

Blaine County, OK (Zone 7a) Long season
200 days
Last Spring Frost April 10
200 growing days
First Fall Frost October 27

Blaine County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (60 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 29 – Aug 24
Recommended (50%) ✓ Fits season (60 days to spare)
Transplant: Apr 10 🍅 Harvest: Jul 3 – Aug 28
Safe Start (90%) ✓ Fits season (62 days to spare)
Transplant: Apr 23 🍅 Harvest: Jul 16 – Sep 10

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.

Soil Compatibility in Blaine County

How your county's soil matches Soybeans's growing requirements.

Soil pH

Your soil pH (6.3โ€“7.4) overlaps with Soybeans's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Blaine County is excellent for Soybeans โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Soybeans.

How to Plant Soybeans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Soybeans

2
successive plantings in your 200-day season

Sow every 9.1 weeks. Last sowing by Jun 29 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 651 gal / 100 sq ft

Monthly Watering Guide for Soybeans

Soybeans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Soybeans Needs Rainfall You Supplement Action
Jan โ€” 0.7" 0" โ„๏ธ Dormant
Feb โ€” 0.9" 0" โ„๏ธ Dormant
Mar โ€” 1.8" 0" โ„๏ธ Dormant
Apr 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
May 4.3" 4.4" 0" โœ… Rainfall sufficient
Jun 4.3" 4.4" 0" โœ… Rainfall sufficient
Jul 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Aug 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Sep 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
Oct 4.3" 2" 2.3" ๐Ÿšฟ Regular watering
Nov โ€” 1.1" 0" โ„๏ธ Dormant
Dec โ€” 0.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Blaine County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Soybeans Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Soybeans needs ~1,750 GDD — county provides 3,500 GDD Excellent fit

Soybeans Planting Timeline โ€” Blaine County, OK

Soybeans Planting Calendar

Activity When Date Range
Direct Sow April 17 Apr 17 โ€“ May 8
Harvest July 10 Jul 10 โ€“ Sep 4

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

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

80โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 7a

๐Ÿ“† Growing Season

200 days in Blaine County

Growing Tips for Soybeans in Blaine County

Direct sow Soybeans outdoors after April 10 in Blaine County when soil has warmed and frost danger has passed.

Common pests for Soybeans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Soybeans in Blaine County, OK?

Blaine County is in Zone 7a with an average last frost of April 10. Plan your Soybeans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Blaine County, OK?

Blaine County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 27.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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