Blog

When to Plant Fava Beans in Larimer 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.

Larimer County, Colorado is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 6, giving you a growing season of approximately 157 days.

At an elevation of 7,108 feet, Larimer County receives approximately 23.4 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Fava Beans to ensure they mature before fall.

Larimer County, CO (Zone 5a) Moderate season
157 days
Last Spring Frost May 2
157 growing days
First Fall Frost October 6

Larimer County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jul 14 – Aug 25
Recommended (50%) ✓ Fits season (38 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jul 18 – Aug 29
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Apr 16 Transplant: May 21 🍅 Harvest: Aug 6 – Sep 17

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
0.6″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,130 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Fava Beans needs ~1,138 GDD — county provides 2,041 GDD Excellent fit

Fava Beans Planting Timeline โ€” Larimer County, CO

Fava Beans Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 โ€“ Apr 11
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 18 Apr 18 โ€“ May 9
Fall Sowing July 28 Jul 28 โ€“ Aug 11
Harvest July 18 Jul 18 โ€“ Aug 29

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Fall Sowing Harvest
August Fall Sowing Harvest
September โ€”
October โ€”
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 5a

Growing Season

157 days

Growing Tips for Larimer 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 Larimer County, CO?

Larimer County is in Zone 5a with an average last frost of May 2. Plan your Fava Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Larimer County, CO?

Larimer County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Larimer County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Larimer County, CO. Local conditions may vary. Last updated: April 2026.