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When to Plant Sweet Potatoes in Jack County, TX

Jack County, Texas Zone 8a May

Top priorities for Jack County, Texas gardeners in May

May is a pivotal month for Jack County, Texas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost March 26
Avg. first frost November 9
Soil temp (4") 64°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
  1. Time to start sweet potatoes inside

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

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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.

Jack County, Texas is in USDA Zone 8a. The average last spring frost is March 26 and the first fall frost is November 9, giving you a growing season of approximately 228 days.

At an elevation of 2,081 feet, Jack County receives approximately 66.9 inches of rainfall annually with predominantly clay soil. Summer highs average 89°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.

Jack County, TX (Zone 8a) Long season
228 days
Last Spring Frost March 26
228 growing days
First Fall Frost November 9
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Jack County Soil Profile

Soil Type

Clay

Soil pH

7.3-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Start indoors: Jan 29 Transplant: Apr 2 🍅 Harvest: Jul 2 – Aug 20
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Feb 5 Transplant: Apr 9 🍅 Harvest: Jul 9 – Aug 27
Safe Start (90%) ✓ Fits season (68 days to spare)
Start indoors: Feb 26 Transplant: Apr 30 🍅 Harvest: Jul 30 – Sep 17

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 Jack County

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

Soil pH

Your soil pH (7.3–7.6) is more alkaline than Sweet Potatoes prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (42% clay) in Jack County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Drainage

Drainage is adequate for Sweet Potatoes.

Organic Matter

Organic matter is moderate (3.2%). 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
1.2″/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 2" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 4.3" 3.7" 0.6" 💧 Light watering
Apr 4.3" 8" 0" ✅ Rainfall sufficient
May 4.3" 9.7" 0" ✅ Rainfall sufficient
Jun 4.3" 9.6" 0" ✅ Rainfall sufficient
Jul 4.3" 8.5" 0" ✅ Rainfall sufficient
Aug 4.3" 7.6" 0" ✅ Rainfall sufficient
Sep 4.3" 6.7" 0" ✅ Rainfall sufficient
Oct 4.3" 4.3" 0" ✅ Rainfall sufficient
Nov 4.3" 2.6" 1.7" 💧 Light watering
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Jack 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 ~1,759 GDD — county provides 3,819 GDD Excellent fit

Sweet Potatoes Planting Timeline — Jack County, TX

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 5 Feb 5 – Feb 19
Transplant Outdoors April 9 Apr 9 – Apr 23
Direct Sow April 2 Apr 2 – Apr 23
Harvest July 9 Jul 9 – Aug 27

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
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: too_alkaline

🗺️ USDA Zone

Zone 8a

📆 Growing Season

228 days in Jack County

Growing Tips for Sweet Potatoes in Jack County

Direct sow Sweet Potatoes outdoors after March 26 in Jack County when soil has warmed and frost danger has passed.

With Jack County's clay soil (42% 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 Jack County, TX?

Jack County is in Zone 8a with an average last frost of March 26. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jack County, TX?

Jack County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 26 and first fall frost is November 9.

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Your Jack County Garden Planner — Free

A 24-page printable planner built for Jack 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 Jack County, TX. 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.