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When to Plant Tomatoes in Austin County, TX

Austin County, Texas Zone 9a May

This month in Austin County, Texas

Your Austin County, Texas garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost February 28
Avg. first frost November 29
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Harvest tomatoes as they ripen

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

June will be here before you know it — start on
  • First harvests: tomatoes

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Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Austin County, Texas is in USDA Zone 9a. The average last spring frost is February 28 and the first fall frost is November 29, giving you a growing season of approximately 274 days.

At an elevation of 350 feet, Austin County receives approximately 68.9 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Tomatoes during the growing season. Clay soil retains moisture well for Tomatoes, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Tomatoes root diseases.

Austin County, TX (Zone 9a) Year-round
274 days
Last Spring Frost February 28
274 growing days
First Fall Frost November 29

Austin County Soil Profile

Soil Type

Clay

Soil pH

6.8-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (135 days to spare)
Start indoors: Jan 2 Transplant: Feb 20 🍅 Harvest: Apr 24 – Jul 3
Recommended (50%) ✓ Fits season (134 days to spare)
Start indoors: Jan 17 Transplant: Mar 7 🍅 Harvest: May 9 – Jul 18
Safe Start (90%) ✓ Fits season (134 days to spare)
Start indoors: Feb 8 Transplant: Mar 29 🍅 Harvest: May 31 – Aug 9

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 Austin County

How your county's soil matches Tomatoes's growing requirements.

Soil pH

Your soil pH (6.8–8.1) is more alkaline than Tomatoes prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (41% clay) in Austin County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Tomatoes.

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

5
successive plantings in your 274-day season

Sow every 6.9 weeks. Last sowing by Sep 05 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
1.1″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 434 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Tomatoes

Tomatoes needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Tomatoes Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 5.2" 2.4" 2.8" 🚿 Regular watering
Mar 5.2" 4.3" 0.9" 💧 Light watering
Apr 5.2" 7.2" 0" ✅ Rainfall sufficient
May 5.2" 9.6" 0" ✅ Rainfall sufficient
Jun 5.2" 11.9" 0" ✅ Rainfall sufficient
Jul 5.2" 8.5" 0" ✅ Rainfall sufficient
Aug 5.2" 9.2" 0" ✅ Rainfall sufficient
Sep 5.2" 5.7" 0" ✅ Rainfall sufficient
Oct 5.2" 4.6" 0.6" 💧 Light watering
Nov 5.2" 2.2" 3" 🚿 Regular watering
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Austin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Tomatoes 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.

Tomatoes needs ~1,269 GDD — county provides 4,812 GDD Excellent fit

Tomatoes Planting Timeline — Austin County, TX

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors January 17 Jan 17 – Jan 31
Transplant Outdoors March 7 Mar 7 – Mar 21
Direct Sow February 28 Feb 28 – Mar 21
Harvest May 9 May 9 – Jul 18

Plant 0.5" deep · 24" apart · Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · Only during dry spells

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

274 days in Austin County

Growing Tips for Tomatoes in Austin County

Direct sow Tomatoes outdoors after February 28 in Austin County when soil has warmed and frost danger has passed.

With Austin County's clay soil (41% clay), work in 3-4 inches of compost before planting Tomatoes. Avoid tilling when soil is wet to prevent compaction.

Common pests for Tomatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Recommended Tomatoes Varieties for Austin County

Your long season supports large indeterminate heirloom types

Brandywine (80d) Cherokee Purple (80d) San Marzano (80d) Mortgage Lifter (85d)

Disease-resistant varieties for your humid climate

Mountain Merit (VF) Defiant (LB) Iron Lady (EB/LB/SF)

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35°F, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Austin County, TX?

Austin County is in Zone 9a with an average last frost of February 28. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Austin County, TX?

Austin County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 28 and first fall frost is November 29.

🌱

Your Austin County Garden Planner — Free

A 24-page printable planner built for Austin 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 Austin 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.