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When to Plant Sweet Potatoes in Cullman County, AL

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.

Cullman County, Alabama is in USDA Zone 7a. The average last spring frost is March 28 and the first fall frost is November 2, giving you a growing season of approximately 219 days.

At an elevation of 347 feet, Cullman County receives approximately 53.1 inches of rainfall annually with predominantly clay loam soil. Summer highs average 91ยฐF, 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.

Cullman County, AL (Zone 7a) Long season
219 days
Last Spring Frost March 28
219 growing days
First Fall Frost November 2

Cullman County Soil Profile

Soil Type

Clay Loam

Soil pH

5.4-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: Jul 4 – Aug 22
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Feb 7 Transplant: Apr 11 🍅 Harvest: Jul 11 – Aug 29
Safe Start (90%) ✓ Fits season (63 days to spare)
Start indoors: Mar 1 Transplant: May 3 🍅 Harvest: Aug 2 – Sep 20

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Sweet Potatoes needs ~1,916 GDD — county provides 3,996 GDD Excellent fit

Sweet Potatoes Planting Timeline โ€” Cullman County, AL

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 7 Feb 7 โ€“ Feb 21
Transplant Outdoors April 11 Apr 11 โ€“ Apr 25
Direct Sow April 4 Apr 4 โ€“ Apr 25
Harvest July 11 Jul 11 โ€“ Aug 29

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“120 days

Soil pH

5.5 โ€“ 6.5

USDA Zone

Zone 7a

Growing Season

219 days

Growing Tips for Cullman County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Sweet Potatoes in Cullman County, AL?

Cullman County is in Zone 7a with an average last frost of March 28. Plan your Sweet Potatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Cullman County, AL?

Cullman County, Alabama is in USDA Hardiness Zone 7a. The average last spring frost is March 28 and first fall frost is November 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Cullman County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

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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 Cullman County, AL. Local conditions may vary. Last updated: April 2026.