Blog

When to Plant Edamame in Northumberland County, VA

Northumberland County, Virginia Zone 8a May

Your May game plan for Northumberland County, Virginia

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

Avg. last frost April 5
Avg. first frost November 4
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 14 hrs
A few tasks this May that'll pay off in June
  • First harvests: edamame

Instant PDF download. No spam, unsubscribe any time.

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.

Northumberland County, Virginia is in USDA Zone 8a. The average last spring frost is April 5 and the first fall frost is November 4, giving you a growing season of approximately 213 days.

At an elevation of 207 feet, Northumberland County receives approximately 54.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Edamame during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Edamame root diseases.

Northumberland County, VA (Zone 8a) Long season
213 days
Last Spring Frost April 5
213 growing days
First Fall Frost November 4

Northumberland County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (97 days to spare)
Transplant: Mar 28 🍅 Harvest: Jun 13 – Jul 25
Recommended (50%) ✓ Fits season (94 days to spare)
Transplant: Apr 5 🍅 Harvest: Jun 21 – Aug 2
Safe Start (90%) ✓ Fits season (107 days to spare)
Transplant: Apr 26 🍅 Harvest: Jul 12 – Aug 23

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 Northumberland County

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

Soil pH

Your soil pH (5.4–7.1) overlaps with Edamame's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.5%). 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 213-day season

Sow every 8.6 weeks. Last sowing by Jul 27 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.1″/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 4.4" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 5.2" 0" ❄️ Dormant
Apr 3.9" 4.2" 0" ✅ Rainfall sufficient
May 3.9" 4.5" 0" ✅ Rainfall sufficient
Jun 3.9" 5.5" 0" ✅ Rainfall sufficient
Jul 3.9" 6.5" 0" ✅ Rainfall sufficient
Aug 3.9" 5.3" 0" ✅ Rainfall sufficient
Sep 3.9" 3.7" 0.2" 💧 Light watering
Oct 3.9" 4" 0" ✅ Rainfall sufficient
Nov 3.9" 3.7" 0.2" 💧 Light watering
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Northumberland 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 ~1,662 GDD — county provides 4,047 GDD Excellent fit

Edamame Planting Timeline — Northumberland County, VA

Edamame Planting Calendar

Activity When Date Range
Direct Sow April 12 Apr 12 – May 3
Harvest June 28 Jun 28 – Aug 9

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May Direct Sow
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

213 days in Northumberland County

Growing Tips for Edamame in Northumberland County

Direct sow Edamame outdoors after April 05 in Northumberland 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 Northumberland County, VA?

Northumberland County is in Zone 8a with an average last frost of April 5. Plan your Edamame planting based on this frost date — see the calendar above for exact timing.

What planting zone is Northumberland County, VA?

Northumberland County, Virginia is in USDA Hardiness Zone 8a. The average last spring frost is April 5 and first fall frost is November 4.

🌱

Your Northumberland County Garden Planner — Free

A 24-page printable planner built for Northumberland 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Northumberland County, VA. 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.