Blog

When to Plant Green Beans in Madison County, MT

Green beans are a warm-season staple available as bush or pole types. Bush beans produce a concentrated harvest while pole beans provide a longer picking season.

Madison County, Montana is in USDA Zone 4a. The average last spring frost is June 11 and the first fall frost is September 13, giving you a growing season of approximately 94 days.

At an elevation of 6,394 feet, Madison County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Green Beans to ensure they mature before fall.

Madison County, MT (Zone 4a) Very short season
94 days
Last Spring Frost June 11
94 growing days
First Fall Frost September 13

Madison County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 3 🍅 Harvest: Jul 29 – Sep 23
Recommended (50%) ✗ May not fit
Transplant: Jun 11 🍅 Harvest: Aug 6 – Oct 1
Safe Start (90%) ✗ May not fit
Transplant: Jun 22 🍅 Harvest: Aug 17 – 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 Madison County

How your county's soil matches Green Beans's growing requirements.

Soil pH

Your soil pH (6.6โ€“8.1) is more alkaline than Green Beans prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Madison County is excellent for Green Beans โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Green Beans.

Organic Matter

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

How to Plant Green Beans

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

Succession Planting Green Beans

2
successive plantings in your 94-day season

Sow every 5.7 weeks. Last sowing by Jul 10 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.9″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 246 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Green Beans

Green Beans 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 Green Beans Needs Rainfall You Supplement Action
Jan โ€” 1.5" 0" โ„๏ธ Dormant
Feb โ€” 1.3" 0" โ„๏ธ Dormant
Mar โ€” 2" 0" โ„๏ธ Dormant
Apr โ€” 1.9" 0" โ„๏ธ Dormant
May โ€” 2.3" 0" โ„๏ธ Dormant
Jun 3.9" 1.4" 2.5" ๐Ÿšฟ Regular watering
Jul 3.9" 1.7" 2.2" ๐Ÿšฟ Regular watering
Aug 3.9" 2.2" 1.7" ๐Ÿ’ง Light watering
Sep 3.9" 1.8" 2.1" ๐Ÿšฟ Regular watering
Oct โ€” 1.8" 0" โ„๏ธ Dormant
Nov โ€” 1.4" 0" โ„๏ธ Dormant
Dec โ€” 1.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Junโ€“Sep in Madison County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Green 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" โ€” every day above 50ยฐF 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.

Green Beans needs ~575 GDD — county provides 940 GDD Excellent fit

Green Beans Planting Timeline โ€” Madison County, MT

Green Beans Planting Calendar

Activity When Date Range
Direct Sow June 25 Jun 25 โ€“ Jul 16
Harvest August 20 Aug 20 โ€“ Oct 15

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.9"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

50โ€“65 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

94 days in Madison County

Growing Tips for Green Beans in Madison County

Direct sow Green Beans outdoors after June 11 in Madison County when soil has warmed and frost danger has passed.

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

Madison County receives only 21" of rain annually. Green Beans needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost when soil is warm. Provide sturdy supports for pole varieties. Pick beans regularly when young and tender to encourage continued production.

Recommended Green Beans Varieties for Madison County

Bush beans that mature quickly for short seasons

Provider (50d) Contender (48d) Royal Burgundy (55d)

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic
  • Fennel

Check more plant combinations with our Companion Planting Checker →

๐ŸŒพ Save Your Own Green Beans Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Allow pods to dry fully on vine until they rattle.
Storage Store airtight; viable 4 years at 35ยฐF, under 45% humidity.

Avoid harvesting during damp weather. Isolate 25 ft between varieties.

Frequently Asked Questions

When should I plant Green Beans in Madison County, MT?

Madison County is in Zone 4a with an average last frost of June 11. Plan your Green Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Madison County, MT?

Madison County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is June 11 and first fall frost is September 13.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Madison County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Madison County, MT. Local conditions may vary. Last updated: April 2026.