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When to Plant Soybeans in Barnes County, ND

Barnes County, North Dakota Zone 4a May

Barnes County, North Dakota gardeners: here's your May plan

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Barnes County, North Dakota.

Avg. last frost May 9
Avg. first frost September 29
Soil temp (4") 55°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Direct-sow soybeans

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

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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.

Barnes County, North Dakota is in USDA Zone 4a. The average last spring frost is May 9 and the first fall frost is September 29, giving you a growing season of approximately 143 days.

At an elevation of 623 feet, Barnes County receives approximately 20.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Soybeans to ensure they mature before fall.

Barnes County, ND (Zone 4a) Short season
143 days
Last Spring Frost May 9
143 growing days
First Fall Frost September 29

Barnes County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (6 days to spare)
Transplant: May 1 🍅 Harvest: Jul 24 – Sep 18
Recommended (50%) ✓ Fits season (3 days to spare)
Transplant: May 9 🍅 Harvest: Aug 1 – Sep 26
Safe Start (90%) ✓ Fits season (9 days to spare)
Transplant: May 19 🍅 Harvest: Aug 11 – Oct 6

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 Barnes County

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

Soil pH

Your soil pH (6.3–7.7) overlaps with Soybeans's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Barnes County is excellent for Soybeans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.7%). Annual compost additions will help Soybeans.

How to Plant Soybeans

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

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 506 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 0.5" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 3.2" 1.1" 💧 Light watering
Jun 4.3" 2.8" 1.5" 💧 Light watering
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 2.6" 1.7" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 1.1" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Barnes County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~1,300 GDD — county provides 1,859 GDD Excellent fit

Soybeans Planting Timeline — Barnes County, ND

Soybeans Planting Calendar

Activity When Date Range
Direct Sow May 23 May 23 – Jun 13
Harvest August 15 Aug 15 – Oct 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

143 days in Barnes County

Growing Tips for Soybeans in Barnes County

Direct sow Soybeans outdoors after May 09 in Barnes 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.

Barnes County receives only 20" of rain annually. Soybeans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Barnes County, ND?

Barnes County is in Zone 4a with an average last frost of May 9. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Barnes County, ND?

Barnes County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 9 and first fall frost is September 29.

🌱

Your Barnes County Garden Planner — Free

A 24-page printable planner built for Barnes County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Barnes County, ND. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.