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When to Plant Sweet Potatoes in Dare County, NC

Dare County, North Carolina Zone 9a May

Dare County, North Carolina gardeners: here's your May plan

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

Avg. last frost March 23
Avg. first frost November 21
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.9 hrs
  1. Begin indoor sowing: sweet potatoes

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

To set up a strong June, finish these tasks
  • First harvests: sweet potatoes

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Sweet potatoes are a warm-season root crop that produces nutritious, sweet tubers in orange, white, and purple varieties. They need a long, hot growing season.

Dare County, North Carolina is in USDA Zone 9a. The average last spring frost is March 23 and the first fall frost is November 21, giving you a growing season of approximately 243 days.

At an elevation of 787 feet, Dare County receives approximately 51.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 92°F, providing good warmth for Sweet Potatoes during the growing season. Clay soil retains moisture well for Sweet Potatoes, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Potatoes root diseases.

Dare County, NC (Zone 9a) Long season
243 days
Last Spring Frost March 23
243 growing days
First Fall Frost November 21
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Dare County Soil Profile

Soil Type

Clay Loam

Soil pH

5.3-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (93 days to spare)
Start indoors: Feb 2 Transplant: Mar 23 🍅 Harvest: Jun 22 – Aug 10
Recommended (50%) ✓ Fits season (96 days to spare)
Start indoors: Feb 9 Transplant: Mar 30 🍅 Harvest: Jun 29 – Aug 17
Safe Start (90%) ✓ Fits season (98 days to spare)
Start indoors: Feb 28 Transplant: Apr 18 🍅 Harvest: Jul 18 – Sep 5

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 Dare County

How your county's soil matches Sweet Potatoes's growing requirements.

Soil pH

Your soil pH (5.3–6.6) overlaps with Sweet Potatoes's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Sweet Potatoes

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 223 gal / 100 sq ft

Monthly Watering Guide for Sweet Potatoes

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

Month Sweet Potatoes Needs Rainfall You Supplement Action
Jan 3.9" 0" ❄️ Dormant
Feb 4.5" 0" ❄️ Dormant
Mar 4.3" 5.1" 0" ✅ Rainfall sufficient
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 5.2" 0" ✅ Rainfall sufficient
Aug 4.3" 5.2" 0" ✅ Rainfall sufficient
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 4.2" 0.1" 💧 Light watering
Dec 4.1" 0" ❄️ Dormant

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

Sweet Potatoes 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.

Sweet Potatoes needs ~1,995 GDD — county provides 4,617 GDD Excellent fit

Sweet Potatoes Planting Timeline — Dare County, NC

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 9 Feb 9 – Feb 23
Transplant Outdoors March 30 Mar 30 – Apr 13
Direct Sow March 23 Mar 23 – Apr 13
Harvest June 29 Jun 29 – Aug 17

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Transplant Outdoors 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

1"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

243 days in Dare County

Growing Tips for Sweet Potatoes in Dare County

Direct sow Sweet Potatoes outdoors after March 23 in Dare County when soil has warmed and frost danger has passed.

With Dare County's clay soil (32% clay), work in 3-4 inches of compost before planting Sweet Potatoes. Avoid tilling when soil is wet to prevent compaction.

General growing tips

Plant slips (rooted sprouts) after soil is thoroughly warm. Build raised mounds for better root development. Cure harvested roots at 80-85F for 10 days to develop sweetness.

Companion Planting

Good Companions

Avoid Planting Near

  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Potatoes in Dare County, NC?

Dare County is in Zone 9a with an average last frost of March 23. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dare County, NC?

Dare County, North Carolina is in USDA Hardiness Zone 9a. The average last spring frost is March 23 and first fall frost is November 21.

🌱

Your Dare County Garden Planner — Free

A 24-page printable planner built for Dare County (Zone 9a). 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 Dare 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.