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When to Plant Kidney Beans in Rosebud County, MT

Rosebud County, Montana Zone 4b May

May to-do list for Rosebud County, Montana

Here's what deserves your attention in Rosebud County, Montana this month. Everything below is tailored to Zone 4b and timed around your local frost dates.

Avg. last frost May 11
Avg. first frost October 3
Soil temp (4") 37°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Seed kidney beans outdoors

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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Kidney beans are a popular dry bean variety named for their shape, available in red and white types. They are the classic bean for chili and red beans and rice.

Rosebud County, Montana is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is October 3, giving you a growing season of approximately 145 days.

At an elevation of 6,448 feet, Rosebud County receives approximately 22.8 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Kidney Beans to ensure they mature before fall.

Rosebud County, MT (Zone 4b) Short season
145 days
Last Spring Frost May 11
145 growing days
First Fall Frost October 3
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Rosebud County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Transplant: May 5 🍅 Harvest: Aug 4 – Sep 8
Recommended (50%) ✓ Fits season (19 days to spare)
Transplant: May 11 🍅 Harvest: Aug 10 – Sep 14
Safe Start (90%) ✓ Fits season (18 days to spare)
Transplant: May 23 🍅 Harvest: Aug 22 – 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 Rosebud County

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

Soil pH

Your soil pH (6.4–7.8) overlaps with Kidney Beans's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Rosebud County is excellent for Kidney Beans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Kidney Beans.

How to Plant Kidney Beans

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

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 526 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Kidney Beans

Kidney 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 Kidney Beans Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.2" 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" 2.3" 🚿 Regular watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 4.3" 1.8" 2.5" 🚿 Regular watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Kidney 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.

Kidney Beans needs ~1,268 GDD — county provides 1,885 GDD Excellent fit

Kidney Beans Planting Timeline — Rosebud County, MT

Kidney Beans Planting Calendar

Activity When Date Range
Direct Sow May 25 May 25 – Jun 15
Harvest August 24 Aug 24 – Sep 28

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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

85–110 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

145 days in Rosebud County

Growing Tips for Kidney Beans in Rosebud County

Direct sow Kidney Beans outdoors after May 11 in Rosebud County when soil has warmed and frost danger has passed.

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

Rosebud County receives only 23" of rain annually. Kidney Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after frost. Allow pods to dry completely on the plant. Kidney beans must be thoroughly cooked as raw or undercooked beans contain harmful lectins.

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 Kidney Beans in Rosebud County, MT?

Rosebud County is in Zone 4b with an average last frost of May 11. Plan your Kidney Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rosebud County, MT?

Rosebud County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is October 3.

🌱

Your Rosebud County Garden Planner — Free

A 24-page printable planner built for Rosebud 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 Rosebud 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.