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When to Plant Sweet Potatoes in Washington County, GA

Washington County, Georgia Zone 8b May

Top priorities for Washington County, Georgia gardeners in May

Your garden in Washington County, Georgia is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost March 21
Avg. first frost November 11
Soil temp (4") 71°F
Watering Moderate
Pest pressure High
Daylight 13.7 hrs
  1. Fire up the seed-starting tray: sweet potatoes

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

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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.

Washington County, Georgia is in USDA Zone 8b. The average last spring frost is March 21 and the first fall frost is November 11, giving you a growing season of approximately 235 days.

At an elevation of 277 feet, Washington County receives approximately 50.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 92°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.

Washington County, GA (Zone 8b) Long season
235 days
Last Spring Frost March 21
235 growing days
First Fall Frost November 11

Washington County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (83 days to spare)
Start indoors: Jan 21 Transplant: Mar 25 🍅 Harvest: Jun 24 – Aug 12
Recommended (50%) ✓ Fits season (81 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: Jul 4 – Aug 22
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Jul 22 – Sep 9

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 Washington County

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

Soil pH

Your soil pH (5.5–6.3) is within Sweet Potatoes's preferred range (5.5–6.5).

Soil Texture

The clay loam soil in Washington 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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 208 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 4.3" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 4.3" 4.6" 0" ✅ Rainfall sufficient
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 5.1" 0" ✅ Rainfall sufficient
Aug 4.3" 5.4" 0" ✅ Rainfall sufficient
Sep 4.3" 4.2" 0.1" 💧 Light watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 4.3" 3.9" 0.4" 💧 Light watering
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Washington 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 ~1,995 GDD — county provides 4,465 GDD Excellent fit

Sweet Potatoes Planting Timeline — Washington County, GA

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 · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: ideal

🗺️ USDA Zone

Zone 8b

📆 Growing Season

235 days in Washington County

Growing Tips for Sweet Potatoes in Washington County

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

With Washington County's clay soil (31% 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 Washington County, GA?

Washington 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 Washington County, GA?

Washington County, Georgia is in USDA Hardiness Zone 8b. The average last spring frost is March 21 and first fall frost is November 11.

🌱

Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington 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 Washington County, GA. 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.