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When to Plant Edamame in Pondera County, MT

Pondera County, Montana Zone 4a May

Top priorities for Pondera County, Montana gardeners in May

Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 23
Avg. first frost September 16
Soil temp (4") 28°F
Watering High
Pest pressure Low
Daylight 15 hrs
Before June arrives, get these ready
  • Direct-sowing: 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.

Pondera County, Montana is in USDA Zone 4a. The average last spring frost is May 23 and the first fall frost is September 16, giving you a growing season of approximately 116 days.

At an elevation of 8,118 feet, Pondera County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Edamame to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Edamame successfully. Mulch heavily to conserve soil moisture.

Pondera County, MT (Zone 4a) Short season
116 days
Last Spring Frost May 23
116 growing days
First Fall Frost September 16
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Pondera County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 18 🍅 Harvest: Aug 3 – Sep 14
Recommended (50%) ✗ May not fit
Transplant: May 23 🍅 Harvest: Aug 8 – Sep 19
Safe Start (90%) ✗ May not fit
Transplant: Jun 9 🍅 Harvest: Aug 25 – Oct 6

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 Pondera County

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

Soil pH

Your soil pH (6.6–8.3) is more alkaline than Edamame prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). 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
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 290 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 1.3" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 3.9" 1.9" 2" 🚿 Regular watering
Jun 3.9" 1.4" 2.5" 🚿 Regular watering
Jul 3.9" 1.7" 2.2" 🚿 Regular watering
Aug 3.9" 2" 1.9" 💧 Light watering
Sep 3.9" 1.4" 2.5" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Pondera 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 ~1,006 GDD — county provides 1,334 GDD Excellent fit

Edamame Planting Timeline — Pondera County, MT

Edamame Planting Calendar

Activity When Date Range
Direct Sow June 6 Jun 6 – Jun 27
Harvest August 22 Aug 22 – Oct 3

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Direct Sow
July
August Harvest
September Harvest
October Harvest
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: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

116 days in Pondera County

Growing Tips for Edamame in Pondera County

Direct sow Edamame outdoors after May 23 in Pondera 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.

Pondera 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 Pondera County, MT?

Pondera County is in Zone 4a 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 Pondera County, MT?

Pondera County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 23 and first fall frost is September 16.

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Your Pondera County Garden Planner — Free

A 24-page printable planner built for Pondera County (Zone 4a). 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 Pondera County, MT. 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.