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When to Plant Sweet Potatoes in Sumter County, AL

Sumter County, Alabama Zone 8b May

May to-do list for Sumter County, Alabama

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

Avg. last frost March 21
Avg. first frost November 8
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
  1. Start sweet potatoes under lights

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

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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.

Sumter County, Alabama is in USDA Zone 8b. The average last spring frost is March 21 and the first fall frost is November 8, giving you a growing season of approximately 232 days.

At an elevation of 335 feet, Sumter County receives approximately 56.6 inches of rainfall annually with predominantly clay loam soil. Summer highs average 94°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.

Sumter County, AL (Zone 8b) Long season
232 days
Last Spring Frost March 21
232 growing days
First Fall Frost November 8

Sumter County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (82 days to spare)
Start indoors: Jan 20 Transplant: Mar 24 🍅 Harvest: Jun 23 – Aug 11
Recommended (50%) ✓ Fits season (78 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: Jul 4 – Aug 22
Safe Start (90%) ✓ Fits season (77 days to spare)
Start indoors: Feb 19 Transplant: Apr 23 🍅 Harvest: Jul 23 – Sep 10

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 Sumter County

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

Soil pH

Your soil pH (5.6–6.2) is within Sweet Potatoes's preferred range (5.5–6.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). 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
1.0″/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 5" 0" ❄️ Dormant
Feb 5" 0" ❄️ Dormant
Mar 4.3" 5.2" 0" ✅ Rainfall sufficient
Apr 4.3" 4.7" 0" ✅ Rainfall sufficient
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 5.2" 0" ✅ Rainfall sufficient
Aug 4.3" 5.9" 0" ✅ Rainfall sufficient
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.3" 3.7" 0.6" 💧 Light watering
Nov 4.3" 4" 0.3" 💧 Light watering
Dec 4.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Sumter 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 ~2,152 GDD — county provides 4,756 GDD Excellent fit

Sweet Potatoes Planting Timeline — Sumter County, AL

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors April 4 Apr 4 – Apr 18
Direct Sow March 28 Mar 28 – Apr 18
Harvest July 4 Jul 4 – Aug 22

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

Month-by-Month Timeline

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

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 8b

📆 Growing Season

232 days in Sumter County

Growing Tips for Sweet Potatoes in Sumter County

Direct sow Sweet Potatoes outdoors after March 21 in Sumter County when soil has warmed and frost danger has passed.

With Sumter 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 Sumter County, AL?

Sumter County is in Zone 8b with an average last frost of March 21. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sumter County, AL?

Sumter County, Alabama is in USDA Hardiness Zone 8b. The average last spring frost is March 21 and first fall frost is November 8.

🌱

Your Sumter County Garden Planner — Free

A 24-page printable planner built for Sumter County (Zone 8b). 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 Sumter County, AL. 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.