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When to Plant Edamame in Chatham County, NC

Chatham County, North Carolina Zone 8a May

May in Chatham County, North Carolina — your action list

Your garden in Chatham County, North Carolina is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost March 28
Avg. first frost November 6
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
Get ahead of June
  • First harvests: edamame

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Edamame are soybeans harvested at the immature green stage for a sweet, nutty snack. They are high in protein and easy to grow in warm climates.

Chatham County, North Carolina is in USDA Zone 8a. The average last spring frost is March 28 and the first fall frost is November 6, giving you a growing season of approximately 223 days.

At an elevation of 1,042 feet, Chatham County receives approximately 48.2 inches of rainfall annually with predominantly clay loam soil. Summer highs average 90°F, providing good warmth for Edamame during the growing season. Clay soil retains moisture well for Edamame, but amend with compost to improve drainage and prevent root rot.

Chatham County, NC (Zone 8a) Long season
223 days
Last Spring Frost March 28
223 growing days
First Fall Frost November 6
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Chatham County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (106 days to spare)
Transplant: Mar 22 🍅 Harvest: Jun 7 – Jul 19
Recommended (50%) ✓ Fits season (104 days to spare)
Transplant: Mar 28 🍅 Harvest: Jun 13 – Jul 25
Safe Start (90%) ✓ Fits season (98 days to spare)
Transplant: Apr 15 🍅 Harvest: Jul 1 – Aug 12

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 Chatham County

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

Soil pH

Your soil pH (5.5–6.4) is more acidic than Edamame prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The clay loam soil in Chatham County is excellent for Edamame — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Edamame.

How to Plant Edamame

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

Succession Planting Edamame

3
successive plantings in your 223-day season

Sow every 8.6 weeks. Last sowing by Jul 29 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Edamame

Edamame needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Edamame Needs Rainfall You Supplement Action
Jan 4.2" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 3.9" 4.3" 0" ✅ Rainfall sufficient
Apr 3.9" 3.9" 0" ✅ Rainfall sufficient
May 3.9" 4" 0" ✅ Rainfall sufficient
Jun 3.9" 4.6" 0" ✅ Rainfall sufficient
Jul 3.9" 4.4" 0" ✅ Rainfall sufficient
Aug 3.9" 4.5" 0" ✅ Rainfall sufficient
Sep 3.9" 4.2" 0" ✅ Rainfall sufficient
Oct 3.9" 2.7" 1.2" 💧 Light watering
Nov 3.9" 4.2" 0" ✅ Rainfall sufficient
Dec 3.5" 0" ❄️ Dormant

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

Edamame 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.

Edamame needs ~1,531 GDD — county provides 3,902 GDD Excellent fit

Edamame Planting Timeline — Chatham County, NC

Edamame Planting Calendar

Activity When Date Range
Direct Sow April 4 Apr 4 – Apr 25
Harvest June 20 Jun 20 – Aug 1

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

Month-by-Month Timeline

MonthActivities
January
February
March
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

0.9"/week · Natural rainfall sufficient

📅 Days to Maturity

75–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8a

📆 Growing Season

223 days in Chatham County

Growing Tips for Edamame in Chatham County

Direct sow Edamame outdoors after March 28 in Chatham County when soil has warmed and frost danger has passed.

With Chatham County's clay soil (28% clay), work in 3-4 inches of compost before planting Edamame. Avoid tilling when soil is wet to prevent compaction.

Common pests for Edamame 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. Do not over-fertilize with nitrogen. Harvest when pods are plump and bright green but before they start to yellow. Steam or boil pods before eating.

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 Edamame in Chatham County, NC?

Chatham County is in Zone 8a with an average last frost of March 28. Plan your Edamame planting based on this frost date — see the calendar above for exact timing.

What planting zone is Chatham County, NC?

Chatham County, North Carolina is in USDA Hardiness Zone 8a. The average last spring frost is March 28 and first fall frost is November 6.

🌱

Your Chatham County Garden Planner — Free

A 24-page printable planner built for Chatham 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 Chatham County, NC. Local conditions may vary. Last updated: May 2026.

Sources & credits

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