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When to Plant Edamame in Warren County, IA

Warren County, Iowa Zone 5b May

Top priorities for Warren County, Iowa gardeners in May

May is a pivotal month for Warren County, Iowa gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 26
Avg. first frost October 9
Soil temp (4") 58°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
  1. Scatter edamame into prepared beds

    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.

Warren County, Iowa is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 9, giving you a growing season of approximately 166 days.

At an elevation of 853 feet, Warren County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Edamame during the growing season.

Warren County, IA (Zone 5b) Moderate season
166 days
Last Spring Frost April 26
166 growing days
First Fall Frost October 9
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Warren County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Transplant: Apr 18 🍅 Harvest: Jul 4 – Aug 15
Recommended (50%) ✓ Fits season (47 days to spare)
Transplant: Apr 26 🍅 Harvest: Jul 12 – Aug 23
Safe Start (90%) ✓ Fits season (47 days to spare)
Transplant: May 11 🍅 Harvest: Jul 27 – Sep 7

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 Warren County

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

Soil pH

Your soil pH (5.9–6.7) overlaps with Edamame's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — Edamame will thrive.

How to Plant Edamame

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

Succession Planting Edamame

2
successive plantings in your 166-day season

Sow every 8.6 weeks. Last sowing by Jul 01 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.8″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 190 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 1.2" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 3.9" 3.1" 0.8" 💧 Light watering
May 3.9" 3.5" 0.4" 💧 Light watering
Jun 3.9" 3.7" 0.2" 💧 Light watering
Jul 3.9" 3.2" 0.7" 💧 Light watering
Aug 3.9" 3.4" 0.5" 💧 Light watering
Sep 3.9" 2.6" 1.3" 💧 Light watering
Oct 3.9" 2.4" 1.5" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Warren 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 ~1,334 GDD — county provides 2,531 GDD Excellent fit

Edamame Planting Timeline — Warren County, IA

Edamame Planting Calendar

Activity When Date Range
Direct Sow May 3 May 3 – May 24
Harvest July 19 Jul 19 – Aug 30

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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Only during dry spells

📅 Days to Maturity

75–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

166 days in Warren County

Growing Tips for Edamame in Warren County

Direct sow Edamame outdoors after April 26 in Warren 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 Warren County, IA?

Warren County is in Zone 5b with an average last frost of April 26. Plan your Edamame planting based on this frost date — see the calendar above for exact timing.

What planting zone is Warren County, IA?

Warren County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 9.

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Your Warren County Garden Planner — Free

A 24-page printable planner built for Warren County (Zone 5b). 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 Warren County, IA. 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.