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When to Plant Fava Beans in Dawson County, MT

Dawson County, Montana Zone 4a May

This month in Dawson County, Montana

Your garden in Dawson County, Montana is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 14
Avg. first frost September 22
Soil temp (4") 36°F
Watering Moderate
Pest pressure Low
Daylight 14.9 hrs
  1. Get fava beans in the ground

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Outdoor sowing time: fava beans

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

June will be here before you know it — start on
  • Starting indoors: fava beans
  • Fall sowing: fava beans

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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.

Dawson County, Montana is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 22, giving you a growing season of approximately 131 days.

At an elevation of 6,445 feet, Dawson County receives approximately 21.9 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Fava Beans to ensure they mature before fall.

Dawson County, MT (Zone 4a) Short season
131 days
Last Spring Frost May 14
131 growing days
First Fall Frost September 22
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Dawson County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (12 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Jul 26 – Sep 6
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jul 30 – Sep 10
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: Apr 15 Transplant: May 27 🍅 Harvest: Aug 12 – Sep 23

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 Dawson County

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

Soil pH

Your soil pH (6.8–8.2) is more alkaline than Fava Beans prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Fava Beans.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Fava Beans.

How to Plant Fava Beans

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 836 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Fava Beans

Fava 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 Fava Beans Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Fava 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.

Fava Beans needs ~875 GDD — county provides 1,310 GDD Excellent fit

Fava Beans Planting Timeline — Dawson County, MT

Fava Beans Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest July 30 Jul 30 – Sep 10
Fall Sowing June 30 Jun 30 – Jul 14

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

75–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

131 days in Dawson County

Growing Tips for Fava Beans in Dawson County

Direct sow Fava Beans outdoors after May 14 in Dawson County when soil has warmed and frost danger has passed.

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

Dawson County receives only 22" of rain annually. Fava Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fava Beans in Dawson County, MT?

Dawson County is in Zone 4a with an average last frost of May 14. Plan your Fava Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dawson County, MT?

Dawson County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 22.

🌱

Your Dawson County Garden Planner — Free

A 24-page printable planner built for Dawson County (Zone 4a). 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 Dawson 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.