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When to Plant Soybeans in Montgomery County, IL

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.

Montgomery County, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 21, giving you a growing season of approximately 191 days.

At an elevation of 1,331 feet, Montgomery County receives approximately 30.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Soybeans during the growing season.

Montgomery County, IL (Zone 6a) Moderate season
191 days
Last Spring Frost April 13
191 growing days
First Fall Frost October 21

Montgomery County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (51 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 29 – Aug 24
Recommended (50%) ✓ Fits season (51 days to spare)
Transplant: Apr 13 🍅 Harvest: Jul 6 – Aug 31
Safe Start (90%) ✓ Fits season (46 days to spare)
Transplant: Apr 28 🍅 Harvest: Jul 21 – Sep 15

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 1,085 gal / 100 sq ft
Soybeans needs ~1,600 GDD — county provides 3,056 GDD Excellent fit

Soybeans Planting Timeline โ€” Montgomery County, IL

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 6a

Growing Season

191 days

Growing Tips for Montgomery 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 Montgomery County, IL?

Montgomery County is in Zone 6a 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 Montgomery County, IL?

Montgomery County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Montgomery County gardeners in Zone 6a 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 Montgomery County, IL. Local conditions may vary. Last updated: April 2026.