Blog

When to Plant Collard Greens in Johnston County, NC

Johnston County, North Carolina Zone 8a May

Your May game plan for Johnston County, North Carolina

A quick May briefing for Johnston County, North Carolina gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 3
Avg. first frost November 3
Soil temp (4") 66°F
Watering Moderate
Pest pressure Moderate
Daylight 13.9 hrs
  1. Begin indoor sowing: collard greens

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Pick collard greens

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

A few tasks this May that'll pay off in June
  • First harvests: collard greens

Instant PDF download. No spam, unsubscribe any time.

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.

Johnston County, North Carolina is in USDA Zone 8a. The average last spring frost is April 3 and the first fall frost is November 3, giving you a growing season of approximately 214 days.

At an elevation of 1,120 feet, Johnston County receives approximately 49.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 92°F, providing good warmth for Collard Greens during the growing season. Clay soil retains moisture well for Collard Greens, but amend with compost to improve drainage and prevent root rot.

Johnston County, NC (Zone 8a) Long season
214 days
Last Spring Frost April 3
214 growing days
First Fall Frost November 3
Share this guide:

Johnston County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (95 days to spare)
Start indoors: Feb 20 Transplant: Mar 27 🍅 Harvest: May 22 – Jul 24
Recommended (50%) ✓ Fits season (95 days to spare)
Start indoors: Feb 27 Transplant: Apr 3 🍅 Harvest: May 29 – Jul 31
Safe Start (90%) ✓ Fits season (84 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 25

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 Johnston County

How your county's soil matches Collard Greens's growing requirements.

Soil pH

Your soil pH (5.6–6.7) overlaps with Collard Greens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Collard Greens.

Organic Matter

Organic matter is moderate (2.6%). 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 214-day season

Sow every 6.3 weeks. Last sowing by Aug 20 to harvest before frost.

For a dedicated fall crop, sow by Aug 25.

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 4.4" 0" ❄️ Dormant
Feb 4.4" 0" ❄️ Dormant
Mar 5.3" 0" ❄️ Dormant
Apr 3.5" 4.1" 0" ✅ Rainfall sufficient
May 3.5" 3.3" 0.2" 💧 Light watering
Jun 3.5" 4.4" 0" ✅ Rainfall sufficient
Jul 3.5" 4.4" 0" ✅ Rainfall sufficient
Aug 3.5" 4.1" 0" ✅ Rainfall sufficient
Sep 3.5" 4.2" 0" ✅ Rainfall sufficient
Oct 3.5" 2.7" 0.8" 💧 Light watering
Nov 3.5" 3.9" 0" ✅ Rainfall sufficient
Dec 4.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Johnston 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 4,066 GDD Excellent fit

Collard Greens Planting Timeline — Johnston County, NC

Collard Greens Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors April 3 Apr 3 – Apr 17
Direct Sow March 20 Mar 20 – Apr 10
Harvest May 29 May 29 – Jul 31
Fall Sowing August 25 Aug 25 – Sep 8

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

Month-by-Month Timeline

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

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 8a

📆 Growing Season

214 days in Johnston County

Growing Tips for Collard Greens in Johnston County

Direct sow Collard Greens outdoors after April 03 in Johnston County when soil has warmed and frost danger has passed.

With Johnston County's clay soil (34% clay), work in 3-4 inches of compost before planting Collard Greens. Avoid tilling when soil is wet to prevent compaction.

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 Johnston County, NC?

Johnston County is in Zone 8a with an average last frost of April 3. Plan your Collard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Johnston County, NC?

Johnston County, North Carolina is in USDA Hardiness Zone 8a. The average last spring frost is April 3 and first fall frost is November 3.

🌱

Your Johnston County Garden Planner — Free

A 24-page printable planner built for Johnston 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Johnston County, NC. 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.