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When to Plant Cowpeas in Grundy County, TN

Grundy County, Tennessee Zone 7b May

Grundy County, Tennessee gardeners: here's your May plan

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 6
Avg. first frost October 29
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
To set up a strong June, finish these tasks
  • First harvests: cowpeas

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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.

Grundy County, Tennessee is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.

At an elevation of 1,205 feet, Grundy County receives approximately 47.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Cowpeas during the growing season.

Grundy County, TN (Zone 7b) Long season
206 days
Last Spring Frost April 6
206 growing days
First Fall Frost October 29

Grundy County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (103 days to spare)
Transplant: Mar 29 🍅 Harvest: May 31 – Jul 12
Recommended (50%) ✓ Fits season (101 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 8 – Jul 20
Safe Start (90%) ✓ Fits season (102 days to spare)
Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 2

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 Grundy County

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

Soil pH

Your soil pH (5.5–6.7) is within Cowpeas's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Grundy County is excellent for Cowpeas — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Cowpeas.

How to Plant Cowpeas

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

Succession Planting Cowpeas

4
successive plantings in your 206-day season

Sow every 6.9 weeks. Last sowing by Jul 31 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 4.2" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 5.4" 0" ❄️ Dormant
Apr 2.2" 3.8" 0" ✅ Rainfall sufficient
May 2.2" 3.9" 0" ✅ Rainfall sufficient
Jun 2.2" 4.4" 0" ✅ Rainfall sufficient
Jul 2.2" 5.1" 0" ✅ Rainfall sufficient
Aug 2.2" 4.3" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.7" 0" ✅ Rainfall sufficient
Nov 3.6" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Grundy County). Supplement amounts are based on average rainfall — 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" — 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.

Cowpeas needs ~1,425 GDD — county provides 3,914 GDD Excellent fit

Cowpeas Planting Timeline — Grundy County, TN

Cowpeas Planting Calendar

Activity When Date Range
Direct Sow April 13 Apr 13 – May 4
Harvest June 15 Jun 15 – Jul 27

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 7b

📆 Growing Season

206 days in Grundy County

Growing Tips for Cowpeas in Grundy County

Direct sow Cowpeas outdoors after April 06 in Grundy 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 Grundy County, TN?

Grundy County is in Zone 7b with an average last frost of April 6. Plan your Cowpeas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grundy County, TN?

Grundy County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is October 29.

🌱

Your Grundy County Garden Planner — Free

A 24-page printable planner built for Grundy County (Zone 7b). 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 Grundy County, TN. 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.