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When to Plant Soybeans in Beaufort County, SC

Beaufort County, South Carolina Zone 9a May

Top priorities for Beaufort County, South Carolina gardeners in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Beaufort County, South Carolina.

Avg. last frost March 13
Avg. first frost November 15
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.

Beaufort County, South Carolina is in USDA Zone 9a. The average last spring frost is March 13 and the first fall frost is November 15, giving you a growing season of approximately 247 days.

At an elevation of 288 feet, Beaufort County receives approximately 56.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95°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.

Beaufort County, SC (Zone 9a) Long season
247 days
Last Spring Frost March 13
247 growing days
First Fall Frost November 15
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Beaufort County Soil Profile

Soil Type

Sandy Loam

Soil pH

4.9-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (107 days to spare)
Transplant: Mar 4 🍅 Harvest: May 27 – Jul 22
Recommended (50%) ✓ Fits season (107 days to spare)
Transplant: Mar 13 🍅 Harvest: Jun 5 – Jul 31
Safe Start (90%) ✓ Fits season (100 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 Beaufort County

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

Soil pH

Your soil pH (4.9–6.1) is more acidic than Soybeans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Beaufort 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 low (1.8%). 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 247-day season

Sow every 9.1 weeks. Last sowing by Jul 18 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
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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" 0" ✅ Rainfall sufficient
Apr 4.3" 4.6" 0" ✅ Rainfall sufficient
May 4.3" 5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 5.3" 0" ✅ Rainfall sufficient
Aug 4.3" 5.4" 0" ✅ Rainfall sufficient
Sep 4.3" 4.8" 0" ✅ Rainfall sufficient
Oct 4.3" 4.1" 0.2" 💧 Light watering
Nov 4.3" 4" 0.3" 💧 Light watering
Dec 4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Beaufort 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 ~2,125 GDD — county provides 5,248 GDD Excellent fit

Soybeans Planting Timeline — Beaufort County, SC

Soybeans Planting Calendar

Activity When Date Range
Direct Sow March 20 Mar 20 – Apr 10
Harvest June 12 Jun 12 – Aug 7

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 · Natural rainfall sufficient

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

247 days in Beaufort County

Growing Tips for Soybeans in Beaufort County

Direct sow Soybeans outdoors after March 13 in Beaufort County when soil has warmed and frost danger has passed.

Sandy soil in Beaufort 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 Beaufort County, SC?

Beaufort County is in Zone 9a with an average last frost of March 13. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Beaufort County, SC?

Beaufort County, South Carolina is in USDA Hardiness Zone 9a. The average last spring frost is March 13 and first fall frost is November 15.

🌱

Your Beaufort County Garden Planner — Free

A 24-page printable planner built for Beaufort 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 Beaufort 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.