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When to Plant Sweet Potatoes in Graham County, NC

Graham County, North Carolina Zone 7b May

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

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

Avg. last frost April 18
Avg. first frost October 20
Soil temp (4") 63°F
Watering Moderate
Pest pressure Low
Daylight 13.9 hrs
  1. Move sweet potatoes into the garden

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

Before June arrives, get these ready
  • Starting indoors: 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.

Graham County, North Carolina is in USDA Zone 7b. The average last spring frost is April 18 and the first fall frost is October 20, giving you a growing season of approximately 185 days.

At an elevation of 1,058 feet, Graham County receives approximately 49.4 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.

Graham County, NC (Zone 7b) Moderate season
185 days
Last Spring Frost April 18
185 growing days
First Fall Frost October 20
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Graham County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Start indoors: Feb 19 Transplant: Apr 23 🍅 Harvest: Jul 23 – Sep 10
Recommended (50%) ✓ Fits season (31 days to spare)
Start indoors: Feb 28 Transplant: May 2 🍅 Harvest: Aug 1 – Sep 19
Safe Start (90%) ✓ Fits season (27 days to spare)
Start indoors: Mar 16 Transplant: May 18 🍅 Harvest: Aug 17 – Oct 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 Graham County

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

Soil pH

Your soil pH (5.6–6.5) is within Sweet Potatoes's preferred range (5.5–6.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 4.5" 0" ❄️ Dormant
Feb 3.5" 0" ❄️ Dormant
Mar 4.4" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 4.1" 0.2" 💧 Light watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 3.3" 0" ❄️ Dormant
Dec 4.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Graham 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 3,376 GDD Excellent fit

Sweet Potatoes Planting Timeline — Graham County, NC

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest August 1 Aug 1 – Sep 19

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: ideal

🗺️ USDA Zone

Zone 7b

📆 Growing Season

185 days in Graham County

Growing Tips for Sweet Potatoes in Graham County

Direct sow Sweet Potatoes outdoors after April 18 in Graham County when soil has warmed and frost danger has passed.

With Graham County's clay soil (26% 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 Graham County, NC?

Graham County is in Zone 7b with an average last frost of April 18. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Graham County, NC?

Graham County, North Carolina is in USDA Hardiness Zone 7b. The average last spring frost is April 18 and first fall frost is October 20.

🌱

Your Graham County Garden Planner — Free

A 24-page printable planner built for Graham 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 Graham 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.