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When to Plant Soybeans in Calhoun County, SC

Calhoun County, South Carolina Zone 8b May

What to do in May

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 March 17
Avg. first frost November 17
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
A few tasks this May that'll pay off in June
  • First harvests: soybeans

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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.

Calhoun County, South Carolina is in USDA Zone 8b. The average last spring frost is March 17 and the first fall frost is November 17, giving you a growing season of approximately 245 days.

At an elevation of 447 feet, Calhoun County receives approximately 51.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 92°F, providing good warmth for Soybeans during the growing season. Sandy soil warms quickly in spring — great for early planting — but Soybeans will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Soybeans root diseases.

Calhoun County, SC (Zone 8b) Long season
245 days
Last Spring Frost March 17
245 growing days
First Fall Frost November 17
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Calhoun County Soil Profile

Soil Type

Sandy Loam

Soil pH

5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (105 days to spare)
Transplant: Mar 8 🍅 Harvest: May 31 – Jul 26
Recommended (50%) ✓ Fits season (105 days to spare)
Transplant: Mar 17 🍅 Harvest: Jun 9 – Aug 4
Safe Start (90%) ✓ Fits season (104 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 23 – Aug 18

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 Calhoun County

How your county's soil matches Soybeans's growing requirements.

Soil pH

Your soil pH (5.0–6.3) is more acidic than Soybeans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Calhoun County warms quickly in spring but drains fast. Soybeans will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Soybeans.

How to Plant Soybeans

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

Succession Planting Soybeans

3
successive plantings in your 245-day season

Sow every 9.1 weeks. Last sowing by Jul 20 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 259 gal / 100 sq ft

Monthly Watering Guide for Soybeans

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

Month Soybeans Needs Rainfall You Supplement Action
Jan 4.1" 0" ❄️ Dormant
Feb 4" 0" ❄️ Dormant
Mar 4.3" 5.3" 0" ✅ Rainfall sufficient
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 5.7" 0" ✅ Rainfall sufficient
Aug 4.3" 5" 0" ✅ Rainfall sufficient
Sep 4.3" 3.9" 0.4" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 4.3" 3.9" 0.4" 💧 Light watering
Dec 3.9" 0" ❄️ Dormant

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

Soybeans 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.

Soybeans needs ~1,900 GDD — county provides 4,655 GDD Excellent fit

Soybeans Planting Timeline — Calhoun County, SC

Soybeans Planting Calendar

Activity When Date Range
Direct Sow March 24 Mar 24 – Apr 14
Harvest June 16 Jun 16 – Aug 11

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

245 days in Calhoun County

Growing Tips for Soybeans in Calhoun County

Direct sow Soybeans outdoors after March 17 in Calhoun County when soil has warmed and frost danger has passed.

Sandy soil in Calhoun County dries quickly — mulch Soybeans with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Common pests for Soybeans 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 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Soybeans in Calhoun County, SC?

Calhoun County is in Zone 8b with an average last frost of March 17. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Calhoun County, SC?

Calhoun County, South Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 17 and first fall frost is November 17.

🌱

Your Calhoun County Garden Planner — Free

A 24-page printable planner built for Calhoun County (Zone 8b). 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 Calhoun 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.