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When to Plant Fava Beans in Deer Lodge County, MT

Fava beans are a cool-season legume with large, meaty beans inside thick pods. They fix nitrogen in the soil and are one of the oldest cultivated crops.

Deer Lodge County, Montana is in USDA Zone 4a. The average last spring frost is June 15 and the first fall frost is September 7, giving you a growing season of approximately 84 days.

At an elevation of 6,928 feet, Deer Lodge County receives approximately 16.8 inches of rainfall annually with predominantly loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Fava Beans to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Fava Beans successfully. Mulch heavily to conserve soil moisture.

Deer Lodge County, MT (Zone 4a) Very short season
84 days
Last Spring Frost June 15
84 growing days
First Fall Frost September 7

Deer Lodge County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 28 Transplant: Jun 9 🍅 Harvest: Aug 25 – Oct 6
Recommended (50%) ✗ May not fit
Start indoors: May 4 Transplant: Jun 15 🍅 Harvest: Aug 31 – Oct 12
Safe Start (90%) ✗ May not fit
Start indoors: May 12 Transplant: Jun 23 🍅 Harvest: Sep 8 – Oct 20

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 144 gal / 100 sq ft
Drought risk

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

Fava Beans needs ~941 GDD — county provides 903 GDD Tight fit

Fava Beans Planting Timeline โ€” Deer Lodge County, MT

Fava Beans Planting Calendar

Activity When Date Range
Start Indoors May 4 May 4 โ€“ May 18
Transplant Outdoors June 15 Jun 15 โ€“ Jun 29
Direct Sow June 8 Jun 8 โ€“ Jun 29
Fall Sowing June 15 Jun 15 โ€“ Jun 29
Harvest August 31 Aug 31 โ€“ Oct 12

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Start Indoors
June Transplant Outdoors Direct Sow Fall Sowing
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

75โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4a

Growing Season

84 days

Growing Tips for Deer Lodge County

Direct sow as early as soil can be worked in spring. Pinch growing tips when pods begin to form to redirect energy and reduce aphid problems. Stake tall varieties.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Level Up Your Garden

Frequently Asked Questions

When should I plant Fava Beans in Deer Lodge County, MT?

Deer Lodge County is in Zone 4a with an average last frost of June 15. Plan your Fava Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Deer Lodge County, MT?

Deer Lodge County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is June 15 and first fall frost is September 7.

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Plan Your Garden with Confidence

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

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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 Deer Lodge County, MT. Local conditions may vary. Last updated: April 2026.