Blog

When to Plant Christmas Lima Beans in Flathead County, MT

Flathead County, Montana Zone 5a May

May in Flathead County, Montana — your action list

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

Avg. last frost June 3
Avg. first frost September 10
Soil temp (4") 41°F
Watering High
Pest pressure Low
Daylight 15 hrs
June prep starts now
  • Transplants going out: christmas lima beans
  • Direct-sowing: christmas lima beans

Instant PDF download. No spam, unsubscribe any time.

Christmas lima beans are a large, beautifully marbled heirloom bean with a rich, chestnut-like flavor. They are a climbing variety that produces generously in warm weather.

Flathead County, Montana is in USDA Zone 5a. The average last spring frost is June 3 and the first fall frost is September 10, giving you a growing season of approximately 99 days.

At an elevation of 6,233 feet, Flathead County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Christmas Lima Beans during the growing season.

Flathead County, MT (Zone 5a) Very short season
99 days
Last Spring Frost June 3
99 growing days
First Fall Frost September 10
Share this guide:

Flathead County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 27 Transplant: Jun 5 🍅 Harvest: Aug 28 – Oct 2
Recommended (50%) ✗ May not fit
Start indoors: Apr 8 Transplant: Jun 17 🍅 Harvest: Sep 9 – Oct 14
Safe Start (90%) ✗ May not fit
Start indoors: Apr 27 Transplant: Jul 6 🍅 Harvest: Sep 28 – Nov 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 Flathead County

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

Soil pH

Your soil pH (6.6–8.4) is more alkaline than Christmas Lima Beans prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

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

How to Plant Christmas Lima Beans

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 129 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Christmas Lima Beans

Christmas Lima 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 Christmas Lima Beans Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 2.7" 0" ❄️ Dormant
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 1.5" 2.8" 🚿 Regular watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 1.9" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Christmas 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.

Christmas Lima Beans needs ~1,372 GDD — county provides 1,509 GDD Good fit

Christmas Lima Beans Planting Timeline — Flathead County, MT

Christmas Lima Beans Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors June 17 Jun 17 – Jul 1
Direct Sow June 10 Jun 10 – Jul 1
Harvest September 9 Sep 9 – Oct 14

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

99 days in Flathead County

Growing Tips for Christmas Lima Beans in Flathead County

Direct sow Christmas Lima Beans outdoors after June 03 in Flathead County when soil has warmed and frost danger has passed.

Your 99.0-day growing season in Flathead County is tight for Christmas Lima Beans (80.0-100.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Flathead County receives only 21" of rain annually. Christmas Lima 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 trellising for vigorous vines. Harvest for fresh shelling when pods are plump or allow to dry on the vine for storage.

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 Christmas Lima Beans in Flathead County, MT?

Flathead County is in Zone 5a with an average last frost of June 3. Plan your Christmas Lima Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Flathead County, MT?

Flathead County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 3 and first fall frost is September 10.

🌱

Your Flathead County Garden Planner — Free

A 24-page printable planner built for Flathead 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.

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 Flathead 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.