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When to Plant Fava Beans in Routt County, CO

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.

Routt County, Colorado is in USDA Zone 4a. The average last spring frost is June 12 and the first fall frost is September 8, giving you a growing season of approximately 88 days.

At an elevation of 5,381 feet, Routt County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Fava Beans to ensure they mature before fall.

Routt County, CO (Zone 4a) Very short season
88 days
Last Spring Frost June 12
88 growing days
First Fall Frost September 8

Routt County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 21 Transplant: Jun 2 🍅 Harvest: Aug 18 – Sep 29
Recommended (50%) ✗ May not fit
Start indoors: May 1 Transplant: Jun 12 🍅 Harvest: Aug 28 – Oct 9
Safe Start (90%) ✗ May not fit
Start indoors: May 14 Transplant: Jun 25 🍅 Harvest: Sep 10 – Oct 22

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
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Fava Beans needs ~1,072 GDD — county provides 1,078 GDD Good fit

Fava Beans Planting Timeline โ€” Routt County, CO

Fava Beans Planting Calendar

Activity When Date Range
Start Indoors May 1 May 1 โ€“ May 15
Transplant Outdoors June 12 Jun 12 โ€“ Jun 26
Direct Sow June 5 Jun 5 โ€“ Jun 26
Fall Sowing June 16 Jun 16 โ€“ Jun 30
Harvest August 28 Aug 28 โ€“ Oct 9

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

88 days

Growing Tips for Routt 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 Routt County, CO?

Routt County is in Zone 4a with an average last frost of June 12. Plan your Fava Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Routt County, CO?

Routt County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 12 and first fall frost is September 8.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Routt 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 Routt County, CO. Local conditions may vary. Last updated: April 2026.