When to Plant Sweet Potatoes in Starr 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.
Starr County, Texas is in USDA Zone 9b. The average last spring frost is February 3 and the first fall frost is December 16, giving you a growing season of approximately 316 days.
At an elevation of 2,451 feet, Starr County receives approximately 55.4 inches of rainfall annually with predominantly loam soil. Summer highs average 98°F, 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.
Starr County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.5
Drainage
Well Drained
Plant Planting Risk Windows
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 Starr County
How your county's soil matches Sweet Potatoes's growing requirements.
Soil pH
Your soil pH (6.8–7.5) is more alkaline than Sweet Potatoes prefers (5.5–6.5). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Starr County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.1%). Annual compost additions will help Sweet Potatoes.
How to Plant Sweet Potatoes
Plant Water Budget
Water stress score is 6/10 — 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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Mar | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Apr | 4.3" | 6.6" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 8.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 7.6" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 6.4" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4" | 0.3" | 💧 Light watering |
| Nov | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Dec | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
Water needs are for active growing months only (Feb–Dec in Starr 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 Planting Timeline — Starr County, TX
Sweet Potatoes Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 23 | Dec 23 – Jan 6 |
| Transplant Outdoors | February 10 | Feb 10 – Feb 24 |
| Direct Sow | February 3 | Feb 3 – Feb 24 |
| Harvest | May 12 | May 12 – Jun 30 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Transplant Outdoors Direct Sow |
| March | — |
| April | — |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | Start Indoors |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 9b
📆 Growing Season
316 days in Starr County
Growing Tips for Sweet Potatoes in Starr County
Direct sow Sweet Potatoes outdoors after February 03 in Starr County when soil has warmed and frost danger has passed.
With summer highs reaching 98°F in Starr County, provide afternoon shade for Sweet Potatoes and water deeply in the morning.
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
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Sweet Potatoes in Other Locations
Frequently Asked Questions
When should I plant Sweet Potatoes in Starr County, TX?
Starr County is in Zone 9b with an average last frost of February 3. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.
What planting zone is Starr County, TX?
Starr County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 3 and first fall frost is December 16.
Plan Your Garden with Confidence
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