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When to Plant Edamame in Wheatland County, MT

Wheatland County, Montana Zone 4b May

Your May gardening checklist

We've pulled the most time-sensitive tasks for Wheatland County, Montana this May and put them front and centre. Tackle them in order.

Avg. last frost May 19
Avg. first frost September 21
Soil temp (4") 29°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
June prep starts now
  • 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.

Wheatland County, Montana is in USDA Zone 4b. The average last spring frost is May 19 and the first fall frost is September 21, giving you a growing season of approximately 125 days.

At an elevation of 7,916 feet, Wheatland County receives approximately 19.2 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.

Wheatland County, MT (Zone 4b) Short season
125 days
Last Spring Frost May 19
125 growing days
First Fall Frost September 21

Wheatland County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (8 days to spare)
Transplant: May 12 🍅 Harvest: Jul 28 – Sep 8
Recommended (50%) ✓ Fits season (6 days to spare)
Transplant: May 19 🍅 Harvest: Aug 4 – Sep 15
Safe Start (90%) ✓ Fits season (14 days to spare)
Transplant: May 30 🍅 Harvest: Aug 15 – Sep 26

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 Wheatland County

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

Soil pH

Your soil pH (6.6–7.8) is more alkaline than Edamame prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). 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 1-2 times/week
Season total 340 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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.3" 0" ❄️ Dormant
May 3.9" 2" 1.9" 💧 Light watering
Jun 3.9" 1.2" 2.7" 🚿 Regular watering
Jul 3.9" 1.9" 2" 🚿 Regular watering
Aug 3.9" 1.8" 2.1" 🚿 Regular watering
Sep 3.9" 1.6" 2.3" 🚿 Regular watering
Oct 1.9" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Wheatland 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 1,437 GDD Excellent fit

Edamame Planting Timeline — Wheatland County, MT

Edamame Planting Calendar

Activity When Date Range
Direct Sow June 2 Jun 2 – Jun 23
Harvest August 18 Aug 18 – Sep 29

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
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 4b

📆 Growing Season

125 days in Wheatland County

Growing Tips for Edamame in Wheatland County

Direct sow Edamame outdoors after May 19 in Wheatland 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.

Wheatland County receives only 19" 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 Wheatland County, MT?

Wheatland County is in Zone 4b with an average last frost of May 19. Plan your Edamame planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wheatland County, MT?

Wheatland County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 19 and first fall frost is September 21.

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Your Wheatland County Garden Planner — Free

A 24-page printable planner built for Wheatland County (Zone 4b). 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 Wheatland 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.