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When to Plant Fennel in Duplin County, NC

Duplin County, North Carolina Zone 8a May

Your May planting checklist for Duplin County, North Carolina

We've pulled the most time-sensitive tasks for Duplin County, North Carolina this May and put them front and centre. Tackle them in order.

Avg. last frost March 23
Avg. first frost November 8
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Start fennel under lights

    Label every cell. You will absolutely forget which is which otherwise.

Looking ahead to June
  • First harvests: fennel

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Florence fennel is grown for its swollen bulb-like stem base, which has a mild anise flavor. It is crisp raw in salads and sweet when roasted or braised.

Duplin County, North Carolina is in USDA Zone 8a. The average last spring frost is March 23 and the first fall frost is November 8, giving you a growing season of approximately 230 days.

At an elevation of 829 feet, Duplin County receives approximately 45.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 96°F, so Fennel may need afternoon shade and extra watering during peak heat. Clay soil retains moisture well for Fennel, but amend with compost to improve drainage and prevent root rot.

Duplin County, NC (Zone 8a) Long season
230 days
Last Spring Frost March 23
230 growing days
First Fall Frost November 8

Duplin County Soil Profile

Soil Type

Clay Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (115 days to spare)
Start indoors: Jan 24 Transplant: Mar 28 🍅 Harvest: May 30 – Jul 11
Recommended (50%) ✓ Fits season (111 days to spare)
Start indoors: Feb 2 Transplant: Apr 6 🍅 Harvest: Jun 8 – Jul 20
Safe Start (90%) ✓ Fits season (106 days to spare)
Start indoors: Feb 27 Transplant: May 1 🍅 Harvest: Jul 3 – Aug 14

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 Duplin County

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

Soil pH

Your soil pH (5.3–6.5) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Fennel.

How to Plant Fennel

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

Succession Planting Fennel

4
successive plantings in your 230-day season

Sow every 6.9 weeks. Last sowing by Aug 10 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Fennel

Fennel needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Fennel Needs Rainfall You Supplement Action
Jan 3.6" 0" ❄️ Dormant
Feb 3.3" 0" ❄️ Dormant
Mar 2.6" 4" 0" ✅ Rainfall sufficient
Apr 2.6" 3.5" 0" ✅ Rainfall sufficient
May 2.6" 3.8" 0" ✅ Rainfall sufficient
Jun 2.6" 4" 0" ✅ Rainfall sufficient
Jul 2.6" 4.7" 0" ✅ Rainfall sufficient
Aug 2.6" 5.2" 0" ✅ Rainfall sufficient
Sep 2.6" 3.1" 0" ✅ Rainfall sufficient
Oct 2.6" 3.1" 0" ✅ Rainfall sufficient
Nov 2.6" 3.2" 0" ✅ Rainfall sufficient
Dec 4.4" 0" ❄️ Dormant

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

Fennel 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.

Fennel needs ~1,650 GDD — county provides 5,060 GDD Excellent fit

Fennel Planting Timeline — Duplin County, NC

Fennel 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 8 Jun 8 – Jul 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

230 days in Duplin County

Growing Tips for Fennel in Duplin County

Direct sow Fennel outdoors after March 23 in Duplin County when soil has warmed and frost danger has passed.

With Duplin County's clay soil (26% clay), work in 3-4 inches of compost before planting Fennel. Avoid tilling when soil is wet to prevent compaction.

With summer highs reaching 96°F in Duplin County, provide afternoon shade for Fennel and water deeply in the morning.

Common pests for Fennel in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in late summer for fall harvest to reduce bolting. Hill soil around bulbs as they enlarge. Harvest when bulbs are tennis-ball sized before they elongate.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel in Duplin County, NC?

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

What planting zone is Duplin County, NC?

Duplin County, North Carolina is in USDA Hardiness Zone 8a. The average last spring frost is March 23 and first fall frost is November 8.

🌱

Your Duplin County Garden Planner — Free

A 24-page printable planner built for Duplin 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.

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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 Duplin 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.