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When to Plant Yard Long Beans in Stephenson County, IL

Yard long beans are a tropical legume that produces slender pods up to 24 inches long. They are a staple in Southeast Asian cooking and thrive in hot weather.

Stephenson County, Illinois is in USDA Zone 5a. The average last spring frost is April 23 and the first fall frost is October 13, giving you a growing season of approximately 173 days.

At an elevation of 1,345 feet, Stephenson County receives approximately 36.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Yard Long Beans during the growing season.

Stephenson County, IL (Zone 5a) Moderate season
173 days
Last Spring Frost April 23
173 growing days
First Fall Frost October 13

Stephenson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (62 days to spare)
Start indoors: Feb 21 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 8
Recommended (50%) ✓ Fits season (61 days to spare)
Start indoors: Feb 26 Transplant: May 7 🍅 Harvest: Jul 2 – Aug 13
Safe Start (90%) ✓ Fits season (59 days to spare)
Start indoors: Mar 14 Transplant: May 23 🍅 Harvest: Jul 18 – Aug 29

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
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 224 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Yard Long Beans needs ~928 GDD — county provides 2,378 GDD Excellent fit

Yard Long Beans Planting Timeline โ€” Stephenson County, IL

Yard Long Beans Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 โ€“ Mar 12
Transplant Outdoors May 7 May 7 โ€“ May 21
Direct Sow April 30 Apr 30 โ€“ May 21
Harvest July 2 Jul 2 โ€“ Aug 13

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

55โ€“80 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5a

Growing Season

173 days

Growing Tips for Stephenson County

Direct sow after soil is warm. Provide tall poles or trellising as vines can reach 8-10 feet. Harvest when pods are pencil-thick before seeds bulge. Cook quickly for best texture.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Level Up Your Garden

Frequently Asked Questions

When should I plant Yard Long Beans in Stephenson County, IL?

Stephenson County is in Zone 5a with an average last frost of April 23. Plan your Yard Long Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Stephenson County, IL?

Stephenson County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 23 and first fall frost is October 13.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Stephenson County gardeners in Zone 5a 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 Stephenson County, IL. Local conditions may vary. Last updated: April 2026.