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When to Plant Sunflower in New Hanover County, NC

New Hanover County, North Carolina Zone 8b May

Your May gardening checklist

Here's what deserves your attention in New Hanover County, North Carolina this month. Everything below is tailored to Zone 8b and timed around your local frost dates.

Avg. last frost March 23
Avg. first frost November 16
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 13.8 hrs
  1. Fire up the seed-starting tray: sunflower

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

Looking ahead to June
  • First harvests: sunflower

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Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

New Hanover County, North Carolina is in USDA Zone 8b. The average last spring frost is March 23 and the first fall frost is November 16, giving you a growing season of approximately 238 days.

At an elevation of 674 feet, New Hanover County receives approximately 43.1 inches of rainfall annually with predominantly clay loam soil. Summer highs average 90°F, providing good warmth for Sunflower during the growing season. Clay soil retains moisture well for Sunflower, but amend with compost to improve drainage and prevent root rot.

New Hanover County, NC (Zone 8b) Long season
238 days
Last Spring Frost March 23
238 growing days
First Fall Frost November 16
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New Hanover County Soil Profile

Soil Type

Clay Loam

Soil pH

5.3-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (104 days to spare)
Start indoors: Jan 24 Transplant: Mar 28 🍅 Harvest: Jun 6 – Jul 25
Recommended (50%) ✓ Fits season (105 days to spare)
Start indoors: Feb 2 Transplant: Apr 6 🍅 Harvest: Jun 15 – Aug 3
Safe Start (90%) ✓ Fits season (102 days to spare)
Start indoors: Feb 19 Transplant: Apr 23 🍅 Harvest: Jul 2 – Aug 20

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 New Hanover County

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

Soil pH

Your soil pH (5.3–6.2) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The clay loam soil in New Hanover County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Sunflower.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Succession Planting Sunflower

4
successive plantings in your 238-day season

Sow every 8 weeks. Last sowing by Aug 08 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

Monthly Watering Guide for Sunflower

Sunflower 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 Sunflower Needs Rainfall You Supplement Action
Jan 3.5" 0" ❄️ Dormant
Feb 3.3" 0" ❄️ Dormant
Mar 2.2" 4.3" 0" ✅ Rainfall sufficient
Apr 2.2" 3.1" 0" ✅ Rainfall sufficient
May 2.2" 3.6" 0" ✅ Rainfall sufficient
Jun 2.2" 3.5" 0" ✅ Rainfall sufficient
Jul 2.2" 5.2" 0" ✅ Rainfall sufficient
Aug 2.2" 4.3" 0" ✅ Rainfall sufficient
Sep 2.2" 3.1" 0" ✅ Rainfall sufficient
Oct 2.2" 2.6" 0" ✅ Rainfall sufficient
Nov 2.2" 3.2" 0" ✅ Rainfall sufficient
Dec 3.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in New Hanover County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sunflower 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.

Sunflower needs ~1,488 GDD — county provides 4,165 GDD Excellent fit

Sunflower Planting Timeline — New Hanover County, NC

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 2 Feb 2 – Feb 16
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow March 30 Mar 30 – Apr 20
Harvest June 15 Jun 15 – Aug 3

Plant 1" deep · 18" apart · Rows 30" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

238 days in New Hanover County

Growing Tips for Sunflower in New Hanover County

Direct sow Sunflower outdoors after March 23 in New Hanover County when soil has warmed and frost danger has passed.

With New Hanover County's clay soil (27% clay), work in 3-4 inches of compost before planting Sunflower. Avoid tilling when soil is wet to prevent compaction.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in New Hanover County, NC?

New Hanover County is in Zone 8b with an average last frost of March 23. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is New Hanover County, NC?

New Hanover County, North Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 23 and first fall frost is November 16.

🌱

Your New Hanover County Garden Planner — Free

A 24-page printable planner built for New Hanover County (Zone 8b). 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 New Hanover 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.