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When to Plant Fennel (herb) in Duplin County, NC

Duplin County, North Carolina Zone 8a May

May in the garden — 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 harvesting fennel (herb)

    If you can't use it all right away, check the food-preservation section of your planner.

Looking ahead to June
  • First harvests: fennel (herb)

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Herb fennel is grown for its aromatic leaves, stalks, and seeds rather than a bulb. It has a strong anise flavor and its flowers attract beneficial insects.

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 (herb) may need afternoon shade and extra watering during peak heat. Clay soil retains moisture well for Fennel (herb), 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
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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 (108 days to spare)
Start indoors: Feb 7 Transplant: Mar 7 🍅 Harvest: May 9 – Jul 18
Recommended (50%) ✓ Fits season (104 days to spare)
Start indoors: Feb 16 Transplant: Mar 16 🍅 Harvest: May 18 – Jul 27
Safe Start (90%) ✓ Fits season (99 days to spare)
Start indoors: Mar 13 Transplant: Apr 10 🍅 Harvest: Jun 12 – Aug 21

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 (herb)'s growing requirements.

Soil pH

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

Soil Texture

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

Organic Matter

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

How to Plant Fennel (herb)

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 Fennel (herb)

4
successive plantings in your 230-day season

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

For a dedicated fall crop, sow by Aug 30.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 331 gal / 100 sq ft

Monthly Watering Guide for Fennel (herb)

Fennel (herb) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Fennel (herb) Needs Rainfall You Supplement Action
Jan 3.6" 0" ❄️ Dormant
Feb 3.3" 0" ❄️ Dormant
Mar 4.3" 4" 0.3" 💧 Light watering
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 4.7" 0" ✅ Rainfall sufficient
Aug 4.3" 5.2" 0" ✅ Rainfall sufficient
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 3.2" 1.1" 💧 Light watering
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 (herb) 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 (herb) needs ~1,650 GDD — county provides 5,060 GDD Excellent fit

Fennel (herb) Planting Timeline — Duplin County, NC

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 – Mar 2
Transplant Outdoors March 16 Mar 16 – Mar 30
Direct Sow March 9 Mar 9 – Mar 30
Harvest May 18 May 18 – Jul 27
Fall Sowing August 30 Aug 30 – Sep 13

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 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 (herb) in Duplin County

Direct sow Fennel (herb) 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 (herb). Avoid tilling when soil is wet to prevent compaction.

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

Common pests for Fennel (herb) 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 spring or fall. Unlike Florence fennel, herb fennel does not form a bulb. Harvest fronds as needed and seeds when they turn brown. Self-sows readily.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel (herb) in Duplin County, NC?

Duplin County is in Zone 8a with an average last frost of March 23. Plan your Fennel (herb) 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.

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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.