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When to Plant Scarlet Runner Beans in McLean County, IL

Scarlet runner beans are ornamental and edible climbing beans with vivid red flowers that attract hummingbirds. Both the young pods and mature beans are edible.

McLean County, Illinois is in USDA Zone 5a. The average last spring frost is April 18 and the first fall frost is October 18, giving you a growing season of approximately 183 days.

At an elevation of 1,024 feet, McLean County receives approximately 31.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Scarlet Runner Beans during the growing season.

McLean County, IL (Zone 5a) Moderate season
183 days
Last Spring Frost April 18
183 growing days
First Fall Frost October 18

McLean County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (68 days to spare)
Start indoors: Feb 17 Transplant: Apr 28 🍅 Harvest: Jun 30 – Aug 4
Recommended (50%) ✓ Fits season (71 days to spare)
Start indoors: Feb 21 Transplant: May 2 🍅 Harvest: Jul 4 – Aug 8
Safe Start (90%) ✓ Fits season (71 days to spare)
Start indoors: Mar 7 Transplant: May 16 🍅 Harvest: Jul 18 – Aug 22

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
0.3″/week
Watering frequency Only during dry spells
Season total 436 gal / 100 sq ft
Scarlet Runner Beans needs ~1,015 GDD — county provides 2,653 GDD Excellent fit

Scarlet Runner Beans Planting Timeline โ€” McLean County, IL

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors February 21 Feb 21 โ€“ Mar 7
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 25 Apr 25 โ€“ May 16
Harvest July 4 Jul 4 โ€“ Aug 8

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors
April Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Harvest
August Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“80 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

183 days

Growing Tips for McLean County

Provide tall trellising for vigorous vines. Direct sow after frost. Harvest pods young for snap beans or let mature for shelling beans. Tubers are perennial in mild climates.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

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Frequently Asked Questions

When should I plant Scarlet Runner Beans in McLean County, IL?

McLean County is in Zone 5a with an average last frost of April 18. Plan your Scarlet Runner Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is McLean County, IL?

McLean County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 18 and first fall frost is October 18.

๐ŸŒฑ

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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 McLean County, IL. Local conditions may vary. Last updated: April 2026.