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When to Plant Edamame in Custer County, CO

Custer County, Colorado Zone 5b May

May to-do list for Custer County, Colorado

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

Avg. last frost May 23
Avg. first frost September 25
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 14.1 hrs
  1. Scatter edamame into prepared beds

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

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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.

Custer County, Colorado is in USDA Zone 5b. The average last spring frost is May 23 and the first fall frost is September 25, giving you a growing season of approximately 125 days.

At an elevation of 8,115 feet, Custer County receives approximately 18.1 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Edamame during the growing season. With low rainfall, drip irrigation is essential for growing Edamame successfully. Mulch heavily to conserve soil moisture.

Custer County, CO (Zone 5b) Short season
125 days
Last Spring Frost May 23
125 growing days
First Fall Frost September 25

Custer County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Transplant: May 11 🍅 Harvest: Jul 27 – Sep 7
Recommended (50%) ✓ Fits season (6 days to spare)
Transplant: May 23 🍅 Harvest: Aug 8 – Sep 19
Safe Start (90%) ✓ Fits season (1 days to spare)
Transplant: Jun 15 🍅 Harvest: Aug 31 – Oct 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 Custer County

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

Soil pH

Your soil pH (6.5–7.8) is more alkaline than Edamame prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Edamame.

How to Plant Edamame

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

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 390 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 1.1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 3.9" 2.3" 1.6" 💧 Light watering
Jun 3.9" 1.2" 2.7" 🚿 Regular watering
Jul 3.9" 1.4" 2.5" 🚿 Regular watering
Aug 3.9" 2.1" 1.8" 💧 Light watering
Sep 3.9" 1.5" 2.4" 🚿 Regular watering
Oct 1.5" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Custer 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 ~1,269 GDD — county provides 1,812 GDD Excellent fit

Edamame Planting Timeline — Custer County, CO

Edamame Planting Calendar

Activity When Date Range
Direct Sow May 30 May 30 – Jun 20
Harvest August 15 Aug 15 – Sep 26

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow
June Direct Sow
July
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 1-2 times/week

📅 Days to Maturity

75–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

125 days in Custer County

Growing Tips for Edamame in Custer County

Direct sow Edamame outdoors after May 23 in Custer 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.

Custer County receives only 18" of rain annually. Edamame needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Custer County, CO?

Custer County is in Zone 5b with an average last frost of May 23. Plan your Edamame planting based on this frost date — see the calendar above for exact timing.

What planting zone is Custer County, CO?

Custer County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 23 and first fall frost is September 25.

🌱

Your Custer County Garden Planner — Free

A 24-page printable planner built for Custer 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 Custer County, CO. 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.