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When to Plant Edamame in Jefferson County, AL

Jefferson County, Alabama Zone 8a May

Top priorities for Jefferson County, Alabama gardeners in May

Here's what deserves your attention in Jefferson County, Alabama this month. Everything below is tailored to Zone 8a and timed around your local frost dates.

Avg. last frost March 31
Avg. first frost October 31
Soil temp (4") 70°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
A few tasks this May that'll pay off in 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.

Jefferson County, Alabama is in USDA Zone 8a. The average last spring frost is March 31 and the first fall frost is October 31, giving you a growing season of approximately 214 days.

At an elevation of 408 feet, Jefferson County receives approximately 48 inches of rainfall annually with predominantly clay loam soil. Summer highs average 94°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.

Jefferson County, AL (Zone 8a) Long season
214 days
Last Spring Frost March 31
214 growing days
First Fall Frost October 31

Jefferson County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (94 days to spare)
Transplant: Mar 26 🍅 Harvest: Jun 11 – Jul 23
Recommended (50%) ✓ Fits season (95 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 16 – Jul 28
Safe Start (90%) ✓ Fits season (94 days to spare)
Transplant: Apr 19 🍅 Harvest: Jul 5 – Aug 16

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 Jefferson County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Edamame's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Edamame.

Organic Matter

Organic matter is moderate (2.2%). 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 214-day season

Sow every 8.6 weeks. Last sowing by Jul 23 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 4.3" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 3.9" 4.9" 0" ✅ Rainfall sufficient
Apr 3.9" 3.9" 0" ✅ Rainfall sufficient
May 3.9" 4.1" 0" ✅ Rainfall sufficient
Jun 3.9" 4.2" 0" ✅ Rainfall sufficient
Jul 3.9" 4.2" 0" ✅ Rainfall sufficient
Aug 3.9" 4.4" 0" ✅ Rainfall sufficient
Sep 3.9" 3.2" 0.7" 💧 Light watering
Oct 3.9" 3.3" 0.6" 💧 Light watering
Nov 3.3" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Jefferson 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 ~1,794 GDD — county provides 4,387 GDD Excellent fit

Edamame Planting Timeline — Jefferson County, AL

Edamame Planting Calendar

Activity When Date Range
Direct Sow April 7 Apr 7 – Apr 28
Harvest June 23 Jun 23 – Aug 4

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

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: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

214 days in Jefferson County

Growing Tips for Edamame in Jefferson County

Direct sow Edamame outdoors after March 31 in Jefferson County when soil has warmed and frost danger has passed.

With Jefferson County's clay soil (34% 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 Jefferson County, AL?

Jefferson County is in Zone 8a with an average last frost of March 31. Plan your Edamame planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, AL?

Jefferson County, Alabama is in USDA Hardiness Zone 8a. The average last spring frost is March 31 and first fall frost is October 31.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson 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 Jefferson County, AL. 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.