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When to Plant Sweet Potatoes in Stephens County, OK

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.

Stephens County, Oklahoma is in USDA Zone 8a. The average last spring frost is April 6 and the first fall frost is November 1, giving you a growing season of approximately 209 days.

At an elevation of 979 feet, Stephens County receives approximately 26.1 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Sweet Potatoes during the growing season.

Stephens County, OK (Zone 8a) Long season
209 days
Last Spring Frost April 6
209 growing days
First Fall Frost November 1

Stephens County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.6

Drainage

Well Drained

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 0.6" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2.4" 1.9" 💧 Light watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 4.3" 0.8" 3.5" 🚿 Regular watering
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Stephens County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sweet Potatoes Planting Timeline — Stephens County, OK

Sweet Potatoes Planting Calendar

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

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: N/A

🗺️ USDA Zone

Zone 8a

📆 Growing Season

209 days in Stephens County

Growing Tips for Stephens 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Potatoes in Stephens County, OK?

Stephens County is in Zone 8a with an average last frost of April 6. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stephens County, OK?

Stephens County, Oklahoma is in USDA Hardiness Zone 8a. The average last spring frost is April 6 and first fall frost is November 1.

🌱

Your Stephens County Garden Planner — Free

A 22-page printable planner built for Stephens 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 Stephens County, OK. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.