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When to Plant Yard Long Beans in Union County, SC

Union County, South Carolina Zone 8a May

May to-do list for Union County, South Carolina

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 5
Avg. first frost October 31
Soil temp (4") 67°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Start yard long beans indoors

    These need a head start before your last frost (April 5). Sow into cells now so you're ready to transplant in a few weeks.

Get ahead of June
  • First harvests: yard long beans

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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.

Union County, South Carolina is in USDA Zone 8a. The average last spring frost is April 5 and the first fall frost is October 31, giving you a growing season of approximately 209 days.

At an elevation of 478 feet, Union County receives approximately 53.3 inches of rainfall annually with predominantly clay loam soil. Summer highs average 91°F, providing good warmth for Yard Long Beans during the growing season. Clay soil retains moisture well for Yard Long Beans, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Yard Long Beans root diseases.

Union County, SC (Zone 8a) Long season
209 days
Last Spring Frost April 5
209 growing days
First Fall Frost October 31
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Union County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (100 days to spare)
Start indoors: Feb 6 Transplant: Apr 10 🍅 Harvest: Jun 5 – Jul 17
Recommended (50%) ✓ Fits season (97 days to spare)
Start indoors: Feb 15 Transplant: Apr 19 🍅 Harvest: Jun 14 – Jul 26
Safe Start (90%) ✓ Fits season (105 days to spare)
Start indoors: Feb 28 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 8

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.

Soil Compatibility in Union County

How your county's soil matches Yard Long Beans's growing requirements.

Soil pH

Your soil pH (5.7–6.3) overlaps with Yard Long Beans's range (6.0–7.5), though not a perfect match.

Soil Texture

The clay loam soil in Union County is excellent for Yard Long Beans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Yard Long Beans.

How to Plant Yard Long Beans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Yard Long Beans

4
successive plantings in your 209-day season

Sow every 6.3 weeks. Last sowing by Aug 12 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Yard Long Beans

Yard Long Beans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Yard Long Beans Needs Rainfall You Supplement Action
Jan 5.1" 0" ❄️ Dormant
Feb 3.9" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 4.3" 4.5" 0" ✅ Rainfall sufficient
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 5.2" 0" ✅ Rainfall sufficient
Jul 4.3" 5.5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.5" 0" ✅ Rainfall sufficient
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 4.1" 0" ❄️ Dormant
Dec 4.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Union County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Yard Long Beans Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Yard Long Beans needs ~1,232 GDD — county provides 3,814 GDD Excellent fit

Yard Long Beans Planting Timeline — Union County, SC

Yard Long Beans Planting Calendar

Activity When Date Range
Start Indoors February 15 Feb 15 – Mar 1
Transplant Outdoors April 19 Apr 19 – May 3
Direct Sow April 12 Apr 12 – May 3
Harvest June 14 Jun 14 – Jul 26

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

55–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

209 days in Union County

Growing Tips for Yard Long Beans in Union County

Direct sow Yard Long Beans outdoors after April 05 in Union County when soil has warmed and frost danger has passed.

With Union County's clay soil (27% clay), work in 3-4 inches of compost before planting Yard Long Beans. Avoid tilling when soil is wet to prevent compaction.

Common pests for Yard Long Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Yard Long Beans in Union County, SC?

Union County is in Zone 8a with an average last frost of April 5. Plan your Yard Long Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Union County, SC?

Union County, South Carolina is in USDA Hardiness Zone 8a. The average last spring frost is April 5 and first fall frost is October 31.

🌱

Your Union County Garden Planner — Free

A 24-page printable planner built for Union County (Zone 8a). 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 Union County, SC. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.