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When to Plant Collard Greens in Grundy County, TN

Grundy County, Tennessee Zone 7b May

Your May game plan for Grundy County, Tennessee

Welcome to May in Zone 7b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 6
Avg. first frost October 29
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Sow collard greens in trays indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

Get ahead of June
  • First harvests: collard greens

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Collard greens are a heat-tolerant member of the cabbage family with large, sturdy leaves. They are a Southern staple and one of the most nutritious leafy greens.

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 Collard Greens 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
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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 (89 days to spare)
Start indoors: Feb 22 Transplant: Mar 29 🍅 Harvest: May 24 – Jul 26
Recommended (50%) ✓ Fits season (87 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: Jun 1 – Aug 3
Safe Start (90%) ✓ Fits season (88 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jun 14 – Aug 16

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 Collard Greens's growing requirements.

Soil pH

Your soil pH (5.5–6.7) overlaps with Collard Greens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Collard Greens

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 Collard Greens

4
successive plantings in your 206-day season

Sow every 6.3 weeks. Last sowing by Aug 15 to harvest before frost.

For a dedicated fall crop, sow by Aug 20.

Plant Water Budget

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

Monthly Watering Guide for Collard Greens

Collard Greens needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Collard Greens Needs Rainfall You Supplement Action
Jan 4.2" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 5.4" 0" ❄️ Dormant
Apr 3.5" 3.8" 0" ✅ Rainfall sufficient
May 3.5" 3.9" 0" ✅ Rainfall sufficient
Jun 3.5" 4.4" 0" ✅ Rainfall sufficient
Jul 3.5" 5.1" 0" ✅ Rainfall sufficient
Aug 3.5" 4.3" 0" ✅ Rainfall sufficient
Sep 3.5" 3.2" 0.3" 💧 Light watering
Oct 3.5" 2.7" 0.8" 💧 Light watering
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.

Collard Greens 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.

Collard Greens needs ~1,235 GDD — county provides 3,914 GDD Excellent fit

Collard Greens Planting Timeline — Grundy County, TN

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow March 23 Mar 23 – Apr 13
Harvest June 1 Jun 1 – Aug 3
Fall Sowing August 20 Aug 20 – Sep 3

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

55–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

206 days in Grundy County

Growing Tips for Collard Greens in Grundy County

Direct sow Collard Greens outdoors after April 06 in Grundy County when soil has warmed and frost danger has passed.

Common pests for Collard Greens in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors or direct sow 4-6 weeks before last frost. Harvest lower leaves first, leaving the growing tip intact. Flavor improves after exposure to frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Collard Greens in Grundy County, TN?

Grundy County is in Zone 7b with an average last frost of April 6. Plan your Collard Greens 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.