Blog

When to Plant Sweet Potatoes in Webb 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.

Webb County, Texas is in USDA Zone 9a. The average last spring frost is February 9 and the first fall frost is December 9, giving you a growing season of approximately 303 days.

At an elevation of 3,543 feet, Webb County receives approximately 50.9 inches of rainfall annually with predominantly loam soil. Summer highs average 95ยฐF, so Sweet Potatoes may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Potatoes root diseases.

Webb County, TX (Zone 9a) Year-round
303 days
Last Spring Frost February 9
303 growing days
First Fall Frost December 9

Webb County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (170 days to spare)
Start indoors: Dec 8 Transplant: Jan 26 🍅 Harvest: Apr 27 – Jun 15
Recommended (50%) ✓ Fits season (156 days to spare)
Start indoors: Dec 29 Transplant: Feb 16 🍅 Harvest: May 18 – Jul 6
Safe Start (90%) ✓ Fits season (144 days to spare)
Start indoors: Jan 22 Transplant: Mar 12 🍅 Harvest: Jun 11 – Jul 30

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 Webb County

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

Soil pH

Your soil pH (6.6โ€“7.7) is more alkaline than Sweet Potatoes prefers (5.5โ€“6.5). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Webb County is excellent for Sweet Potatoes โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). 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
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 964 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

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€” 1.3" 0" โ„๏ธ Dormant
Feb 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Mar 4.3" 2.8" 1.5" ๐Ÿ’ง Light watering
Apr 4.3" 5" 0" โœ… Rainfall sufficient
May 4.3" 8.3" 0" โœ… Rainfall sufficient
Jun 4.3" 7.6" 0" โœ… Rainfall sufficient
Jul 4.3" 5.9" 0" โœ… Rainfall sufficient
Aug 4.3" 6.4" 0" โœ… Rainfall sufficient
Sep 4.3" 5.2" 0" โœ… Rainfall sufficient
Oct 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Nov 4.3" 1.7" 2.6" ๐Ÿšฟ Regular watering
Dec 4.3" 1.5" 2.8" ๐Ÿšฟ Regular watering

Water needs are for active growing months only (Febโ€“Dec in Webb 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 ~2,231 GDD — county provides 6,460 GDD Excellent fit

Sweet Potatoes Planting Timeline โ€” Webb County, TX

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors December 29 Dec 29 โ€“ Jan 12
Transplant Outdoors February 16 Feb 16 โ€“ Mar 2
Direct Sow February 9 Feb 9 โ€“ Mar 2
Harvest May 18 May 18 โ€“ Jul 6

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 5.5โ€“6.5 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

303 days in Webb County

Growing Tips for Sweet Potatoes in Webb County

Direct sow Sweet Potatoes outdoors after February 09 in Webb 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 Webb County, TX?

Webb County is in Zone 9a with an average last frost of February 9. Plan your Sweet Potatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Webb County, TX?

Webb County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 9 and first fall frost is December 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Webb County gardeners in Zone 9a 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 Webb County, TX. Local conditions may vary. Last updated: April 2026.