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When to Plant Sweet Potatoes in San Augustine County, TX

San Augustine County, Texas Zone 9a April

Top priorities for San Augustine County, Texas gardeners in April

Each item below is timed to San Augustine County, Texas's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 5
Avg. first frost November 16
Soil temp (4") 62°F
Watering Low
Pest pressure High
Daylight 12.8 hrs
  1. Begin indoor sowing: sweet potatoes

    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.

San Augustine County, Texas is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 16, giving you a growing season of approximately 256 days.

At an elevation of 146 feet, San Augustine County receives approximately 62.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Sweet Potatoes may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — 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.

San Augustine County, TX (Zone 9a) Long season
256 days
Last Spring Frost March 5
256 growing days
First Fall Frost November 16
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San Augustine County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.4-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (113 days to spare)
Start indoors: Jan 14 Transplant: Mar 4 🍅 Harvest: Jun 3 – Jul 22
Recommended (50%) ✓ Fits season (109 days to spare)
Start indoors: Jan 22 Transplant: Mar 12 🍅 Harvest: Jun 11 – Jul 30
Safe Start (90%) ✓ Fits season (99 days to spare)
Start indoors: Feb 18 Transplant: Apr 8 🍅 Harvest: Jul 8 – Aug 26

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 San Augustine County

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

Soil pH

Your soil pH (5.4–6.6) overlaps with Sweet Potatoes's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is low (1.8%). 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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 4.3" 3.6" 0.7" 💧 Light watering
Apr 4.3" 6.2" 0" ✅ Rainfall sufficient
May 4.3" 8.2" 0" ✅ Rainfall sufficient
Jun 4.3" 10.7" 0" ✅ Rainfall sufficient
Jul 4.3" 8.7" 0" ✅ Rainfall sufficient
Aug 4.3" 8.2" 0" ✅ Rainfall sufficient
Sep 4.3" 5.8" 0" ✅ Rainfall sufficient
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 4.3" 2.3" 2" 💧 Light watering
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in San Augustine 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 ~2,310 GDD — county provides 5,632 GDD Excellent fit

Sweet Potatoes Planting Timeline — San Augustine County, TX

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors January 22 Jan 22 – Feb 5
Transplant Outdoors March 12 Mar 12 – Mar 26
Direct Sow March 5 Mar 5 – Mar 26
Harvest June 11 Jun 11 – Jul 30

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Transplant Outdoors Direct Sow
April
May
June Harvest
July Harvest
August
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: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

256 days in San Augustine County

Growing Tips for Sweet Potatoes in San Augustine County

Direct sow Sweet Potatoes outdoors after March 05 in San Augustine County when soil has warmed and frost danger has passed.

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

With summer highs reaching 96°F in San Augustine 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

Avoid Planting Near

  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Potatoes in San Augustine County, TX?

San Augustine County is in Zone 9a with an average last frost of March 5. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Augustine County, TX?

San Augustine County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 16.

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Your San Augustine County Garden Planner — Free

A 24-page printable planner built for San Augustine County (Zone 9a). 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 San Augustine County, TX. Local conditions may vary. Last updated: April 2026.

Sources & credits

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