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When to Plant Sweet Potatoes in Clark County, AR

Clark County, Arkansas Zone 8a May

May to-do list for Clark County, Arkansas

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

Avg. last frost March 22
Avg. first frost November 9
Soil temp (4") 66°F
Watering Moderate
Pest pressure Moderate
Daylight 13.8 hrs
  1. Fire up the seed-starting tray: sweet potatoes

    Your window is short. These crops want several weeks of indoor growth before they go outside.

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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.

Clark County, Arkansas is in USDA Zone 8a. The average last spring frost is March 22 and the first fall frost is November 9, giving you a growing season of approximately 232 days.

At an elevation of 1,350 feet, Clark County receives approximately 45.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Sweet Potatoes during the growing season.

Clark County, AR (Zone 8a) Long season
232 days
Last Spring Frost March 22
232 growing days
First Fall Frost November 9
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Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Start indoors: Jan 23 Transplant: Mar 27 🍅 Harvest: Jun 26 – Aug 14
Recommended (50%) ✓ Fits season (78 days to spare)
Start indoors: Feb 1 Transplant: Apr 5 🍅 Harvest: Jul 5 – Aug 23
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Feb 22 Transplant: Apr 26 🍅 Harvest: Jul 26 – Sep 13

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 Clark County

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

Soil pH

Your soil pH (5.7–6.7) overlaps with Sweet Potatoes's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Sweet Potatoes.

Organic Matter

Organic matter is moderate (2.5%). 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
0.8″/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 4.2" 0" ❄️ Dormant
Feb 3.6" 0" ❄️ Dormant
Mar 4.3" 3.6" 0.7" 💧 Light watering
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 5.1" 0" ✅ Rainfall sufficient
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 2.5" 1.8" 💧 Light watering
Nov 4.3" 3.5" 0.8" 💧 Light watering
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Clark 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 4,234 GDD Excellent fit

Sweet Potatoes Planting Timeline — Clark County, AR

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 1 Feb 1 – Feb 15
Transplant Outdoors April 5 Apr 5 – Apr 19
Direct Sow March 29 Mar 29 – Apr 19
Harvest July 5 Jul 5 – Aug 23

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Direct Sow
April Transplant Outdoors Direct Sow
May
June
July Harvest
August Harvest
September
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: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

232 days in Clark County

Growing Tips for Sweet Potatoes in Clark County

Direct sow Sweet Potatoes outdoors after March 22 in Clark County when soil has warmed and frost danger has passed.

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 Clark County, AR?

Clark County is in Zone 8a with an average last frost of March 22. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, AR?

Clark County, Arkansas is in USDA Hardiness Zone 8a. The average last spring frost is March 22 and first fall frost is November 9.

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Your Clark County Garden Planner — Free

A 24-page printable planner built for Clark County (Zone 8a). 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 Clark County, AR. 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.