When to Plant Lima Beans in Missoula County, MT
Missoula County, Montana gardeners: here's your May plan
Welcome to May in Zone 5b. These are the moves that will have the biggest impact on your growing season.
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Outdoor sowing time: lima beans
Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.
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.
Missoula County, Montana is in USDA Zone 5b. The average last spring frost is May 14 and the first fall frost is September 23, giving you a growing season of approximately 132 days.
At an elevation of 8,019 feet, Missoula County receives approximately 15.9 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Lima Beans during the growing season. With low rainfall, drip irrigation is essential for growing Lima Beans successfully. Mulch heavily to conserve soil moisture.
Missoula County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.7
Drainage
Well Drained
Plant Planting Risk Windows
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 Missoula County
How your county's soil matches Lima Beans's growing requirements.
Soil pH
Your soil pH (6.2–7.7) overlaps with Lima Beans's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Missoula County is excellent for Lima Beans — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Lima Beans.
How to Plant Lima Beans
Succession Planting Lima Beans
Sow every 6.9 weeks. Last sowing by Jun 25 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — 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 | — | 1" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 1.7" | 0" | ❄️ Dormant |
| May | 3.9" | 1.7" | 2.2" | 🚿 Regular watering |
| Jun | 3.9" | 1.1" | 2.8" | 🚿 Regular watering |
| Jul | 3.9" | 1.3" | 2.6" | 🚿 Regular watering |
| Aug | 3.9" | 1.9" | 2" | 🚿 Regular watering |
| Sep | 3.9" | 1.4" | 2.5" | 🚿 Regular watering |
| Oct | — | 1.5" | 0" | ❄️ Dormant |
| Nov | — | 1" | 0" | ❄️ Dormant |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Missoula 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 Planting Timeline — Missoula County, MT
Lima Beans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 21 | May 21 – Jun 11 |
| Harvest | July 23 | Jul 23 – Sep 3 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Direct Sow |
| June | Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.9"/week · 1-2 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
132 days in Missoula County
Growing Tips for Lima Beans in Missoula County
Direct sow Lima Beans outdoors after May 14 in Missoula 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.
Missoula County receives only 16" 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
Check more plant combinations with our Companion Planting Checker →
Lima Beans in Other Locations
Frequently Asked Questions
When should I plant Lima Beans in Missoula County, MT?
Missoula County is in Zone 5b with an average last frost of May 14. Plan your Lima Beans planting based on this frost date — see the calendar above for exact timing.
What planting zone is Missoula County, MT?
Missoula County, Montana is in USDA Hardiness Zone 5b. The average last spring frost is May 14 and first fall frost is September 23.
Your Missoula County Garden Planner — Free
A 24-page printable planner built for Missoula County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.