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When to Plant Sweet Potatoes in Iredell County, NC

Iredell County, North Carolina Zone 7b May

May to-do list for Iredell County, North Carolina

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 7
Avg. first frost November 1
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Get sweet potatoes seeds going inside

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

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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.

Iredell County, North Carolina is in USDA Zone 7b. The average last spring frost is April 7 and the first fall frost is November 1, giving you a growing season of approximately 208 days.

At an elevation of 400 feet, Iredell County receives approximately 44.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 91°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.

Iredell County, NC (Zone 7b) Long season
208 days
Last Spring Frost April 7
208 growing days
First Fall Frost November 1

Iredell County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Feb 4 Transplant: Apr 8 🍅 Harvest: Jul 8 – Aug 26
Recommended (50%) ✓ Fits season (54 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jul 21 – Sep 8
Safe Start (90%) ✓ Fits season (53 days to spare)
Start indoors: Mar 3 Transplant: May 5 🍅 Harvest: Aug 4 – Sep 22

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 Iredell County

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

Soil pH

Your soil pH (5.5–6.7) overlaps with Sweet Potatoes's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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 207 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 4" 0" ❄️ Dormant
Feb 3.8" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.9" 0.4" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 4.3" 3.3" 1" 💧 Light watering
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Iredell 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 ~1,916 GDD — county provides 3,796 GDD Excellent fit

Sweet Potatoes Planting Timeline — Iredell County, NC

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 14 Apr 14 – May 5
Harvest July 21 Jul 21 – Sep 8

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

Month-by-Month Timeline

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

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 7b

📆 Growing Season

208 days in Iredell County

Growing Tips for Sweet Potatoes in Iredell County

Direct sow Sweet Potatoes outdoors after April 07 in Iredell County when soil has warmed and frost danger has passed.

With Iredell County's clay soil (30% 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 Iredell County, NC?

Iredell County is in Zone 7b with an average last frost of April 7. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Iredell County, NC?

Iredell County, North Carolina is in USDA Hardiness Zone 7b. The average last spring frost is April 7 and first fall frost is November 1.

🌱

Your Iredell County Garden Planner — Free

A 24-page printable planner built for Iredell County (Zone 7b). 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 Iredell 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.