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When to Plant Fava Beans in Marshall County, OK

Marshall County, Oklahoma Zone 8a May

Your May game plan for Marshall County, Oklahoma

Each item below is timed to Marshall County, Oklahoma's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 24
Avg. first frost November 12
Soil temp (4") 70°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
Before June arrives, get these ready
  • First harvests: 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.

Marshall County, Oklahoma is in USDA Zone 8a. The average last spring frost is March 24 and the first fall frost is November 12, giving you a growing season of approximately 233 days.

At an elevation of 520 feet, Marshall County receives approximately 23.7 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Fava Beans during the growing season.

Marshall County, OK (Zone 8a) Long season
233 days
Last Spring Frost March 24
233 growing days
First Fall Frost November 12

Marshall County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (118 days to spare)
Start indoors: Feb 4 Transplant: Mar 11 🍅 Harvest: May 27 – Jul 8
Recommended (50%) ✓ Fits season (114 days to spare)
Start indoors: Feb 17 Transplant: Mar 24 🍅 Harvest: Jun 9 – Jul 21
Safe Start (90%) ✓ Fits season (111 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jun 30 – Aug 11

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 Marshall County

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

Soil pH

Your soil pH (6.2–7.8) overlaps with Fava Beans's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Marshall 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 (3.5%). Annual compost additions will help Fava Beans.

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.

Succession Planting Fava Beans

3
successive plantings in your 233-day season

Sow every 8.6 weeks. Last sowing by Aug 04 to harvest before frost.

For a dedicated fall crop, sow by Sep 03.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 2,172 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 0.5" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 4.3" 1.6" 2.7" 🚿 Regular watering
Apr 4.3" 2.3" 2" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 3.4" 0.9" 💧 Light watering
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 2.8" 1.5" 💧 Light watering
Sep 4.3" 2.4" 1.9" 💧 Light watering
Oct 4.3" 1.3" 3" 🚿 Regular watering
Nov 4.3" 0.9" 3.4" 🚿 Regular watering
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Marshall 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 ~1,662 GDD — county provides 4,427 GDD Excellent fit

Fava Beans Planting Timeline — Marshall County, OK

Fava Beans Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors March 24 Mar 24 – Apr 7
Direct Sow March 10 Mar 10 – Mar 31
Harvest June 9 Jun 9 – Jul 21
Fall Sowing September 3 Sep 3 – Sep 17

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

Month-by-Month Timeline

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

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: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

233 days in Marshall County

Growing Tips for Fava Beans in Marshall County

Direct sow Fava Beans outdoors after March 24 in Marshall 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.

Marshall County receives only 24" 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 Marshall County, OK?

Marshall County is in Zone 8a with an average last frost of March 24. Plan your Fava Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marshall County, OK?

Marshall County, Oklahoma is in USDA Hardiness Zone 8a. The average last spring frost is March 24 and first fall frost is November 12.

🌱

Your Marshall County Garden Planner — Free

A 24-page printable planner built for Marshall County (Zone 8a). 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 Marshall County, OK. 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.