When to Plant Green Beans in Mercer County, IL
Green beans are a warm-season staple available as bush or pole types. Bush beans produce a concentrated harvest while pole beans provide a longer picking season.
Mercer County, Illinois is in USDA Zone 5a. The average last spring frost is April 17 and the first fall frost is October 15, giving you a growing season of approximately 181 days.
At an elevation of 777 feet, Mercer County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Green Beans to ensure they mature before fall.
Mercer County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-6.7
Drainage
Well Drained
Plant Planting Risk Windows
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
Green Beans Planting Timeline — Mercer County, IL
Green Beans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 24 | Apr 24 – May 15 |
| Harvest | June 19 | Jun 19 – Aug 14 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
50–65 days
Soil pH
6 – 7
USDA Zone
Zone 5a
Growing Season
181 days
Growing Tips for Mercer County
Direct sow after last frost when soil is warm. Provide sturdy supports for pole varieties. Pick beans regularly when young and tender to encourage continued production.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Avoid harvesting during damp weather. Isolate 25 ft between varieties.
Green Beans in Other Locations
Frequently Asked Questions
When should I plant Green Beans in Mercer County, IL?
Mercer County is in Zone 5a with an average last frost of April 17. Plan your Green Beans planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mercer County, IL?
Mercer County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 17 and first fall frost is October 15.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Mercer County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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