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When to Plant Fava Beans in Mountrail County, ND

Mountrail County, North Dakota Zone 4a May

Top priorities for Mountrail County, North Dakota gardeners in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Mountrail County, North Dakota.

Avg. last frost May 17
Avg. first frost September 22
Soil temp (4") 50°F
Watering Moderate
Pest pressure Low
Daylight 15 hrs
  1. Harden off and plant fava beans

    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. Sow fava beans where they'll grow

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

Looking ahead to June
  • 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.

Mountrail County, North Dakota is in USDA Zone 4a. The average last spring frost is May 17 and the first fall frost is September 22, giving you a growing season of approximately 128 days.

At an elevation of 1,059 feet, Mountrail County receives approximately 26.2 inches of rainfall annually with predominantly loam soil. Summer highs average 78°F, so choose short-season varieties of Fava Beans to ensure they mature before fall.

Mountrail County, ND (Zone 4a) Short season
128 days
Last Spring Frost May 17
128 growing days
First Fall Frost September 22

Mountrail County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Jul 28 – Sep 8
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: Apr 5 Transplant: May 17 🍅 Harvest: Aug 2 – Sep 13
Safe Start (90%) ✓ Fits season (11 days to spare)
Start indoors: Apr 17 Transplant: May 29 🍅 Harvest: Aug 14 – Sep 25

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 Mountrail County

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

Soil pH

Your soil pH (6.8–7.5) 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 Mountrail County is excellent for Fava Beans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) — Fava Beans will thrive.

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
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 192 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 2" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 4.3" 2.9" 1.4" 💧 Light watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 2.1" 2.2" 🚿 Regular watering
Aug 4.3" 2.7" 1.6" 💧 Light watering
Sep 4.3" 2.2" 2.1" 💧 Light watering
Oct 2.5" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Mountrail 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 ~744 GDD — county provides 1,088 GDD Excellent fit

Fava Beans Planting Timeline — Mountrail County, ND

Fava Beans Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 17 May 17 – May 31
Direct Sow May 10 May 10 – May 31
Harvest August 2 Aug 2 – Sep 13
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
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

75–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

128 days in Mountrail County

Growing Tips for Fava Beans in Mountrail County

Direct sow Fava Beans outdoors after May 17 in Mountrail 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.

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 Mountrail County, ND?

Mountrail County is in Zone 4a with an average last frost of May 17. Plan your Fava Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mountrail County, ND?

Mountrail County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 17 and first fall frost is September 22.

🌱

Your Mountrail County Garden Planner — Free

A 24-page printable planner built for Mountrail 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 Mountrail County, ND. 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.