Blog

When to Plant Lima Beans in Mineral County, MT

Mineral County, Montana Zone 6a May

Top priorities for Mineral County, Montana gardeners in May

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

Avg. last frost May 30
Avg. first frost September 20
Soil temp (4") 44°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
Coming up in June — start thinking about
  • Direct-sowing: lima beans

Instant PDF download. No spam, unsubscribe any time.

Lima beans are a warm-season legume producing large, creamy beans with a buttery texture. Both bush and pole varieties are available, with pole types yielding more.

Mineral County, Montana is in USDA Zone 6a. The average last spring frost is May 30 and the first fall frost is September 20, giving you a growing season of approximately 113 days.

At an elevation of 5,389 feet, Mineral County receives approximately 12.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Lima Beans to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Lima Beans successfully. Mulch heavily to conserve soil moisture.

Mineral County, MT (Zone 6a) Short season
113 days
Last Spring Frost May 30
113 growing days
First Fall Frost September 20

Mineral County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Transplant: May 14 🍅 Harvest: Jul 16 – Aug 27
Recommended (50%) ✓ Fits season (8 days to spare)
Transplant: May 30 🍅 Harvest: Aug 1 – Sep 12
Safe Start (90%) ✓ Fits season (8 days to spare)
Transplant: Jun 19 🍅 Harvest: Aug 21 – Oct 2

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 Mineral County

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

Soil pH

Your soil pH (6.7–7.7) is more alkaline than Lima Beans prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Lima Beans.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Lima Beans.

How to Plant Lima Beans

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

Succession Planting Lima Beans

2
successive plantings in your 113-day season

Sow every 6.9 weeks. Last sowing by Jun 22 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.5″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 851 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Lima Beans

Lima 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 Lima Beans Needs Rainfall You Supplement Action
Jan 0.9" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.1" 0" ❄️ Dormant
May 3.9" 1.6" 2.3" 🚿 Regular watering
Jun 3.9" 0.9" 3" 🚿 Regular watering
Jul 3.9" 1.2" 2.7" 🚿 Regular watering
Aug 3.9" 1.3" 2.6" 🚿 Regular watering
Sep 3.9" 1.1" 2.8" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

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

Lima 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.

Lima Beans needs ~975 GDD — county provides 1,469 GDD Excellent fit

Lima Beans Planting Timeline — Mineral County, MT

Lima Beans Planting Calendar

Activity When Date Range
Direct Sow June 6 Jun 6 – Jun 27
Harvest August 8 Aug 8 – Sep 19

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 · 2-3 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

113 days in Mineral County

Growing Tips for Lima Beans in Mineral County

Direct sow Lima Beans outdoors after May 30 in Mineral County when soil has warmed and frost danger has passed.

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

Mineral County receives only 12" of rain annually. Lima Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after soil is thoroughly warm at 65F or above. Do not soak seeds before planting as they may crack. Harvest when pods are plump but still green for fresh limas.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic
  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lima Beans in Mineral County, MT?

Mineral County is in Zone 6a with an average last frost of May 30. Plan your Lima Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mineral County, MT?

Mineral County, Montana is in USDA Hardiness Zone 6a. The average last spring frost is May 30 and first fall frost is September 20.

🌱

Your Mineral County Garden Planner — Free

A 24-page printable planner built for Mineral County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Mineral 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.