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When to Plant Sweet Potatoes in Madison 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.

Madison County, Alabama is in USDA Zone 7a. The average last spring frost is April 6 and the first fall frost is October 31, giving you a growing season of approximately 208 days.

At an elevation of 286 feet, Madison County receives approximately 55.3 inches of rainfall annually with predominantly clay loam soil. Summer highs average 90ยฐF, 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.

Madison County, AL (Zone 7a) Long season
208 days
Last Spring Frost April 6
208 growing days
First Fall Frost October 31

Madison County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (56 days to spare)
Start indoors: Feb 6 Transplant: Apr 10 🍅 Harvest: Jul 10 – Aug 28
Recommended (50%) ✓ Fits season (54 days to spare)
Start indoors: Feb 16 Transplant: Apr 20 🍅 Harvest: Jul 20 – Sep 7
Safe Start (90%) ✓ Fits season (54 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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Sweet Potatoes needs ~1,838 GDD — county provides 3,640 GDD Excellent fit

Sweet Potatoes Planting Timeline โ€” Madison County, AL

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 โ€“ Mar 2
Transplant Outdoors April 20 Apr 20 โ€“ May 4
Direct Sow April 13 Apr 13 โ€“ May 4
Harvest July 20 Jul 20 โ€“ Sep 7

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

Month-by-Month Timeline

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

208 days

Growing Tips for Madison 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 Madison County, AL?

Madison County is in Zone 7a with an average last frost of April 6. Plan your Sweet Potatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Madison County, AL?

Madison County, Alabama is in USDA Hardiness Zone 7a. The average last spring frost is April 6 and first fall frost is October 31.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Madison 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 Madison County, AL. Local conditions may vary. Last updated: April 2026.