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When to Plant Yard Long Beans in Big Horn County, MT

Big Horn County, Montana Zone 5a May

Big Horn County, Montana gardeners: here's your May plan

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

Avg. last frost May 13
Avg. first frost September 30
Soil temp (4") 39°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Time to transplant yard long beans

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Plant yard long beans from seed, right in the garden

    These tolerate cool soil, so you're not gambling by sowing now.

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Yard long beans are a tropical legume that produces slender pods up to 24 inches long. They are a staple in Southeast Asian cooking and thrive in hot weather.

Big Horn County, Montana is in USDA Zone 5a. The average last spring frost is May 13 and the first fall frost is September 30, giving you a growing season of approximately 140 days.

At an elevation of 5,955 feet, Big Horn County receives approximately 22.5 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Yard Long Beans to ensure they mature before fall.

Big Horn County, MT (Zone 5a) Short season
140 days
Last Spring Frost May 13
140 growing days
First Fall Frost September 30

Big Horn County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (23 days to spare)
Start indoors: Mar 13 Transplant: May 22 🍅 Harvest: Jul 17 – Aug 28
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Mar 18 Transplant: May 27 🍅 Harvest: Jul 22 – Sep 2
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: Apr 5 Transplant: Jun 14 🍅 Harvest: Aug 9 – Sep 20

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 Big Horn County

How your county's soil matches Yard Long Beans's growing requirements.

Soil pH

Your soil pH (6.2–7.6) overlaps with Yard Long Beans's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Big Horn County is excellent for Yard Long Beans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Yard Long Beans.

How to Plant Yard Long Beans

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

Succession Planting Yard Long Beans

2
successive plantings in your 140-day season

Sow every 6.3 weeks. Last sowing by Jul 12 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 486 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Yard Long Beans

Yard Long Beans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Yard Long Beans Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 4.3" 2.9" 1.4" 💧 Light watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Big Horn County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Yard Long Beans 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.

Yard Long Beans needs ~827 GDD — county provides 1,715 GDD Excellent fit

Yard Long Beans Planting Timeline — Big Horn County, MT

Yard Long Beans Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors May 27 May 27 – Jun 10
Direct Sow May 20 May 20 – Jun 10
Harvest July 22 Jul 22 – Sep 2

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

55–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

140 days in Big Horn County

Growing Tips for Yard Long Beans in Big Horn County

Direct sow Yard Long Beans outdoors after May 13 in Big Horn County when soil has warmed and frost danger has passed.

Common pests for Yard Long Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

Big Horn County receives only 22" of rain annually. Yard Long Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after soil is warm. Provide tall poles or trellising as vines can reach 8-10 feet. Harvest when pods are pencil-thick before seeds bulge. Cook quickly for best texture.

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 Yard Long Beans in Big Horn County, MT?

Big Horn County is in Zone 5a with an average last frost of May 13. Plan your Yard Long Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Big Horn County, MT?

Big Horn County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 13 and first fall frost is September 30.

🌱

Your Big Horn County Garden Planner — Free

A 24-page printable planner built for Big Horn County (Zone 5a). 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 Big Horn 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.