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When to Plant Cowpeas in Jackson County, IL

Cowpeas (black-eyed peas) are a heat-loving legume that fixes nitrogen in the soil. They are drought-tolerant and produce protein-rich pods in hot conditions.

Jackson County, Illinois is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 21, giving you a growing season of approximately 194 days.

At an elevation of 1,046 feet, Jackson County receives approximately 38.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Cowpeas during the growing season.

Jackson County, IL (Zone 6b) Moderate season
194 days
Last Spring Frost April 10
194 growing days
First Fall Frost October 21

Jackson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Transplant: Apr 5 🍅 Harvest: Jun 7 – Jul 19
Recommended (50%) ✓ Fits season (89 days to spare)
Transplant: Apr 10 🍅 Harvest: Jun 12 – Jul 24
Safe Start (90%) ✓ Fits season (87 days to spare)
Transplant: Apr 24 🍅 Harvest: Jun 26 – Aug 7

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 Jackson County

How your county's soil matches Cowpeas's growing requirements.

Soil pH

Your soil pH (6.1โ€“7.1) overlaps with Cowpeas's range (5.5โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Jackson County is excellent for Cowpeas โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Cowpeas.

Organic Matter

Organic matter is excellent (4.1%) โ€” Cowpeas will thrive.

How to Plant Cowpeas

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

Succession Planting Cowpeas

3
successive plantings in your 194-day season

Sow every 6.9 weeks. Last sowing by Jul 23 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/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

Monthly Watering Guide for Cowpeas

Cowpeas needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cowpeas Needs Rainfall You Supplement Action
Jan โ€” 1.8" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 2.7" 0" โ„๏ธ Dormant
Apr 2.2" 3.4" 0" โœ… Rainfall sufficient
May 2.2" 4.1" 0" โœ… Rainfall sufficient
Jun 2.2" 5.8" 0" โœ… Rainfall sufficient
Jul 2.2" 4.3" 0" โœ… Rainfall sufficient
Aug 2.2" 3.9" 0" โœ… Rainfall sufficient
Sep 2.2" 3.7" 0" โœ… Rainfall sufficient
Oct 2.2" 2.9" 0" โœ… Rainfall sufficient
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 2.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Jackson County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Cowpeas 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" โ€” every day above 50ยฐF 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.

Cowpeas needs ~1,256 GDD — county provides 3,249 GDD Excellent fit

Cowpeas Planting Timeline โ€” Jackson County, IL

Cowpeas Planting Calendar

Activity When Date Range
Direct Sow April 17 Apr 17 โ€“ May 8
Harvest June 19 Jun 19 โ€“ Jul 31

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Direct Sow
May Direct Sow
June Harvest
July Harvest
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

194 days in Jackson County

Growing Tips for Cowpeas in Jackson County

Direct sow Cowpeas outdoors after April 10 in Jackson County when soil has warmed and frost danger has passed.

Common pests for Cowpeas in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after soil is thoroughly warm. Do not over-fertilize with nitrogen as cowpeas fix their own. Harvest pods when they begin to dry on the vine for dry beans.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Onion

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cowpeas in Jackson County, IL?

Jackson County is in Zone 6b with an average last frost of April 10. Plan your Cowpeas planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jackson County, IL?

Jackson County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jackson County gardeners in Zone 6b 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 Jackson County, IL. Local conditions may vary. Last updated: April 2026.