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When to Plant Soybeans in Jasper County, SC

Jasper County, South Carolina Zone 9a May

Top priorities for Jasper County, South Carolina gardeners in May

May is a pivotal month for Jasper County, South Carolina gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost March 15
Avg. first frost November 12
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.

Jasper County, South Carolina is in USDA Zone 9a. The average last spring frost is March 15 and the first fall frost is November 12, giving you a growing season of approximately 242 days.

At an elevation of 143 feet, Jasper County receives approximately 60.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Soybeans may need afternoon shade and extra watering during peak heat. 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.

Jasper County, SC (Zone 9a) Long season
242 days
Last Spring Frost March 15
242 growing days
First Fall Frost November 12

Jasper County Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (105 days to spare)
Transplant: Mar 6 🍅 Harvest: May 29 – Jul 24
Recommended (50%) ✓ Fits season (102 days to spare)
Transplant: Mar 15 🍅 Harvest: Jun 7 – Aug 2
Safe Start (90%) ✓ Fits season (97 days to spare)
Transplant: Apr 9 🍅 Harvest: Jul 2 – Aug 27

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 Jasper County

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

Soil pH

Your soil pH (4.8–6.2) is more acidic than Soybeans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Soybeans.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Soybeans.

How to Plant Soybeans

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

Succession Planting Soybeans

3
successive plantings in your 242-day season

Sow every 9.1 weeks. Last sowing by Jul 15 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 4.6" 0" ❄️ Dormant
Feb 4.8" 0" ❄️ Dormant
Mar 4.3" 5.7" 0" ✅ Rainfall sufficient
Apr 4.3" 4.3" 0" ✅ Rainfall sufficient
May 4.3" 5.5" 0" ✅ Rainfall sufficient
Jun 4.3" 5.2" 0" ✅ Rainfall sufficient
Jul 4.3" 5.8" 0" ✅ Rainfall sufficient
Aug 4.3" 5.1" 0" ✅ Rainfall sufficient
Sep 4.3" 5" 0" ✅ Rainfall sufficient
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 4.3" 5.3" 0" ✅ Rainfall sufficient
Dec 5.2" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Jasper 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 ~2,275 GDD — county provides 5,505 GDD Excellent fit

Soybeans Planting Timeline — Jasper County, SC

Soybeans Planting Calendar

Activity When Date Range
Direct Sow March 22 Mar 22 – Apr 12
Harvest June 14 Jun 14 – Aug 9

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

242 days in Jasper County

Growing Tips for Soybeans in Jasper County

Direct sow Soybeans outdoors after March 15 in Jasper County when soil has warmed and frost danger has passed.

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

With summer highs reaching 97°F in Jasper County, provide afternoon shade for Soybeans and water deeply in the morning.

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 Jasper County, SC?

Jasper County is in Zone 9a with an average last frost of March 15. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jasper County, SC?

Jasper County, South Carolina is in USDA Hardiness Zone 9a. The average last spring frost is March 15 and first fall frost is November 12.

🌱

Your Jasper County Garden Planner — Free

A 24-page printable planner built for Jasper County (Zone 9a). 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 Jasper 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.