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When to plant Soybeans in Cass County, MN

Plant Soybeans in Cass County during the brief May 26–June 16 window. With 139 frost-free days, fall plantings can't mature before September 28.

When to Plant Soybeans in Cass County, MN

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.

Cass County, Minnesota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 28, giving you a growing season of approximately 139 days.

At an elevation of 938 feet, Cass County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Soybeans to ensure they mature before fall.

Cass County, MN (Zone 4a) Short season
139 days
Last Spring Frost May 12
139 growing days
First Fall Frost September 28

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Soybeans Planting Timeline — Cass County, MN

Soybeans Planting Calendar

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

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

Moderate — regular watering

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 4a

📆 Growing Season

139 days in Cass County

Growing Tips for Cass 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Soybeans in Cass County, MN?

Cass County is in Zone 4a with an average last frost of May 12. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cass County, MN?

Cass County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 28.

When should I plant Soybeans in Cass County, MN?

In Cass County, MN, plant Soybeans after the last frost (around May 12) and before the first frost (around September 28). Best results when soil holds above 50°F.

What growing zone is Cass County, MN for Soybeans?

Cass County sits in USDA Zone 4a. Soybeans grows reliably in zones 3a through 10b, so it's a good fit here.

Can Soybeans grow in Cass County's climate?

Yes — Soybeans grows well in Cass County's temperate climate. Cass County averages a 139-day frost-free season, with last frost around May 12 and first frost around September 28.

🌱

Your Cass County Garden Planner — Free

A 22-page printable planner built for Cass 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 Cass County, MN. Local conditions may vary. Last updated: July 2026.

Sources & credits

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