Blog

When to Plant Sweet Potatoes in Cass County, TX

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.

Cass County, Texas is in USDA Zone 8a. The average last spring frost is March 14 and the first fall frost is November 16, giving you a growing season of approximately 247 days.

At an elevation of 392 feet, Cass County receives approximately 71.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94ยฐF, providing good warmth for Sweet Potatoes during the growing season. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Sweet Potatoes will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Potatoes root diseases.

Cass County, TX (Zone 8a) Long season
247 days
Last Spring Frost March 14
247 growing days
First Fall Frost November 16

Cass County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (94 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: Jun 19 – Aug 7
Recommended (50%) ✓ Fits season (93 days to spare)
Start indoors: Jan 24 Transplant: Mar 28 🍅 Harvest: Jun 27 – Aug 15
Safe Start (90%) ✓ Fits season (85 days to spare)
Start indoors: Feb 15 Transplant: Apr 19 🍅 Harvest: Jul 19 – Sep 6

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 Cass County

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

Soil pH

Your soil pH (5.6โ€“6.7) overlaps with Sweet Potatoes's range (5.5โ€“6.5), though not a perfect match.

Soil Texture

Sandy soil in Cass County warms quickly in spring but drains fast. Sweet Potatoes will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Sweet Potatoes.

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting 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
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 178 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 โ€” 2" 0" โ„๏ธ Dormant
Feb โ€” 2.5" 0" โ„๏ธ Dormant
Mar 4.3" 4.3" 0" โœ… Rainfall sufficient
Apr 4.3" 6.6" 0" โœ… Rainfall sufficient
May 4.3" 11.3" 0" โœ… Rainfall sufficient
Jun 4.3" 12.4" 0" โœ… Rainfall sufficient
Jul 4.3" 8.9" 0" โœ… Rainfall sufficient
Aug 4.3" 8.7" 0" โœ… Rainfall sufficient
Sep 4.3" 6.7" 0" โœ… Rainfall sufficient
Oct 4.3" 4.3" 0" โœ… Rainfall sufficient
Nov 4.3" 2.4" 1.9" ๐Ÿ’ง Light watering
Dec โ€” 1.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Cass County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 5,063 GDD Excellent fit

Sweet Potatoes Planting Timeline โ€” Cass County, TX

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors January 24 Jan 24 โ€“ Feb 7
Transplant Outdoors March 28 Mar 28 โ€“ Apr 11
Direct Sow March 21 Mar 21 โ€“ Apr 11
Harvest June 27 Jun 27 โ€“ Aug 15

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 5.5โ€“6.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

247 days in Cass County

Growing Tips for Sweet Potatoes in Cass County

Direct sow Sweet Potatoes outdoors after March 14 in Cass County when soil has warmed and frost danger has passed.

Sandy soil in Cass County dries quickly โ€” mulch Sweet Potatoes with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

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 Cass County, TX?

Cass County is in Zone 8a with an average last frost of March 14. Plan your Sweet Potatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Cass County, TX?

Cass County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 14 and first fall frost is November 16.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Cass County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Cass County, TX. Local conditions may vary. Last updated: April 2026.