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When to Plant Fava Beans in Malheur County, OR

Malheur County, Oregon Zone 6b May

Malheur County, Oregon gardeners: here's your May plan

May is a pivotal month for Malheur County, Oregon gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 18
Avg. first frost September 29
Soil temp (4") 55°F
Watering Critical
Pest pressure Low
Daylight 14.5 hrs
  1. Harden off and plant fava beans

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Direct-sow 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

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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.

Malheur County, Oregon is in USDA Zone 6b. The average last spring frost is May 18 and the first fall frost is September 29, giving you a growing season of approximately 134 days.

At an elevation of 2,676 feet, Malheur County receives approximately 17.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Fava Beans during the growing season. With low rainfall, drip irrigation is essential for growing Fava Beans successfully. Mulch heavily to conserve soil moisture.

Malheur County, OR (Zone 6b) Short season
134 days
Last Spring Frost May 18
134 growing days
First Fall Frost September 29
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Malheur County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jul 17 – Aug 28
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Apr 13 Transplant: May 18 🍅 Harvest: Aug 3 – Sep 14
Safe Start (90%) ✓ Fits season (14 days to spare)
Start indoors: May 8 Transplant: Jun 12 🍅 Harvest: Aug 28 – Oct 9

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 Malheur County

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

Soil pH

Your soil pH (5.4–6.3) is more acidic than Fava Beans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Malheur 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 excellent (5.6%) — Fava Beans will thrive.

How to Plant Fava Beans

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

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 896 gal / 100 sq ft

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 2.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 4.3" 0.9" 3.4" 🚿 Regular watering
Jun 4.3" 0.7" 3.6" 🚿 Regular watering
Jul 4.3" 0.3" 4" 🚿 Regular watering
Aug 4.3" 0.3" 4" 🚿 Regular watering
Sep 4.3" 0.8" 3.5" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 2.6" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Malheur 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 ~1,531 GDD — county provides 2,345 GDD Excellent fit

Fava Beans Planting Timeline — Malheur County, OR

Fava Beans Planting Calendar

Activity When Date Range
Start Indoors April 13 Apr 13 – Apr 27
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 4 May 4 – May 25
Harvest August 3 Aug 3 – Sep 14
Fall Sowing July 21 Jul 21 – Aug 4

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 Transplant Outdoors
July Fall Sowing
August Fall Sowing 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_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

134 days in Malheur County

Growing Tips for Fava Beans in Malheur County

Direct sow Fava Beans outdoors after May 18 in Malheur 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.

Malheur County receives only 18" 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 Malheur County, OR?

Malheur County is in Zone 6b with an average last frost of May 18. Plan your Fava Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Malheur County, OR?

Malheur County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is May 18 and first fall frost is September 29.

🌱

Your Malheur County Garden Planner — Free

A 24-page printable planner built for Malheur County (Zone 6b). 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 Malheur County, OR. 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.