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When to Plant Edamame in Middlesex County, MA

Middlesex County, Massachusetts Zone 6b May

May to-do list for Middlesex County, Massachusetts

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

Avg. last frost April 24
Avg. first frost October 17
Soil temp (4") 64°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Direct-sow edamame

    These tolerate cool soil, so you're not gambling by sowing now.

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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.

Middlesex County, Massachusetts is in USDA Zone 6b. The average last spring frost is April 24 and the first fall frost is October 17, giving you a growing season of approximately 176 days.

At an elevation of 117 feet, Middlesex County receives approximately 43.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Edamame during the growing season.

Middlesex County, MA (Zone 6b) Moderate season
176 days
Last Spring Frost April 24
176 growing days
First Fall Frost October 17

Middlesex County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (55 days to spare)
Transplant: Apr 20 🍅 Harvest: Jul 6 – Aug 17
Recommended (50%) ✓ Fits season (57 days to spare)
Transplant: Apr 24 🍅 Harvest: Jul 10 – Aug 21
Safe Start (90%) ✓ Fits season (53 days to spare)
Transplant: May 13 🍅 Harvest: Jul 29 – Sep 9

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 Middlesex County

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

Soil pH

Your soil pH (5.2–6.7) is more acidic than Edamame prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Edamame.

How to Plant Edamame

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

Succession Planting Edamame

2
successive plantings in your 176-day season

Sow every 8.6 weeks. Last sowing by Jul 09 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.0″/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 3.5" 0" ❄️ Dormant
Feb 3.2" 0" ❄️ Dormant
Mar 4.2" 0" ❄️ Dormant
Apr 3.9" 3.2" 0.7" 💧 Light watering
May 3.9" 4.2" 0" ✅ Rainfall sufficient
Jun 3.9" 3.6" 0.3" 💧 Light watering
Jul 3.9" 3.9" 0" ✅ Rainfall sufficient
Aug 3.9" 3.9" 0" ✅ Rainfall sufficient
Sep 3.9" 3.3" 0.6" 💧 Light watering
Oct 3.9" 3.5" 0.4" 💧 Light watering
Nov 3.3" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Middlesex 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 3,080 GDD Excellent fit

Edamame Planting Timeline — Middlesex County, MA

Edamame Planting Calendar

Activity When Date Range
Direct Sow May 1 May 1 – May 22
Harvest July 17 Jul 17 – Aug 28

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow
June
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: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

176 days in Middlesex County

Growing Tips for Edamame in Middlesex County

Direct sow Edamame outdoors after April 24 in Middlesex County when soil has warmed and frost danger has passed.

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 Middlesex County, MA?

Middlesex County is in Zone 6b with an average last frost of April 24. Plan your Edamame planting based on this frost date — see the calendar above for exact timing.

What planting zone is Middlesex County, MA?

Middlesex County, Massachusetts is in USDA Hardiness Zone 6b. The average last spring frost is April 24 and first fall frost is October 17.

🌱

Your Middlesex County Garden Planner — Free

A 24-page printable planner built for Middlesex County (Zone 6b). 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 Middlesex County, MA. 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.