Blog

When to Plant Tomatoes in Martin County, TX

Martin County, Texas Zone 8a May

Your May gardening checklist

We've pulled the most time-sensitive tasks for Martin County, Texas this May and put them front and centre. Tackle them in order.

Avg. last frost March 25
Avg. first frost November 12
Soil temp (4") 53°F
Watering Critical
Pest pressure Moderate
Daylight 13.7 hrs
  1. Start tomatoes under lights

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

June prep starts now
  • First harvests: tomatoes

Instant PDF download. No spam, unsubscribe any time.

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.

Martin County, Texas is in USDA Zone 8a. The average last spring frost is March 25 and the first fall frost is November 12, giving you a growing season of approximately 232 days.

At an elevation of 4,922 feet, Martin County receives approximately 50.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 100°F, so Tomatoes may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Tomatoes will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Tomatoes root diseases.

Martin County, TX (Zone 8a) Long season
232 days
Last Spring Frost March 25
232 growing days
First Fall Frost November 12

Martin County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (83 days to spare)
Start indoors: Jan 27 Transplant: Mar 31 🍅 Harvest: Jun 2 – Aug 11
Recommended (50%) ✓ Fits season (85 days to spare)
Start indoors: Feb 4 Transplant: Apr 8 🍅 Harvest: Jun 10 – Aug 19
Safe Start (90%) ✓ Fits season (79 days to spare)
Start indoors: Feb 23 Transplant: Apr 27 🍅 Harvest: Jun 29 – Sep 7

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 Martin County

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

Soil pH

Your soil pH (7.2–8.7) is more alkaline than Tomatoes prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is low (1.0%). Add 2-3 inches of compost before planting Tomatoes.

How to Plant Tomatoes

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

Succession Planting Tomatoes

4
successive plantings in your 232-day season

Sow every 6.9 weeks. Last sowing by Aug 19 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 722 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 2.9" 0" ❄️ Dormant
Feb 3" 0" ❄️ Dormant
Mar 5.2" 2.4" 2.8" 🚿 Regular watering
Apr 5.2" 1.9" 3.3" 🚿 Regular watering
May 5.2" 0.9" 4.3" 🚿 Regular watering
Jun 5.2" 1.4" 3.8" 🚿 Regular watering
Jul 5.2" 9.2" 0" ✅ Rainfall sufficient
Aug 5.2" 10.1" 0" ✅ Rainfall sufficient
Sep 5.2" 7" 0" ✅ Rainfall sufficient
Oct 5.2" 4.9" 0.3" 💧 Light watering
Nov 5.2" 2.8" 2.4" 💧 Light watering
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Martin 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 ~1,812 GDD — county provides 5,800 GDD Excellent fit

Tomatoes Planting Timeline — Martin County, TX

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors February 4 Feb 4 – Feb 18
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow April 1 Apr 1 – Apr 22
Harvest June 10 Jun 10 – Aug 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · 1-2 times/week

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8a

📆 Growing Season

232 days in Martin County

Growing Tips for Tomatoes in Martin County

Direct sow Tomatoes outdoors after March 25 in Martin County when soil has warmed and frost danger has passed.

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

With summer highs reaching 100°F in Martin County, provide afternoon shade for Tomatoes and water deeply in the morning.

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 Martin County

Heat-set varieties that pollinate reliably above 90°F

Solar Fire Florida 91 Phoenix Heat Wave II

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 Martin County, TX?

Martin County is in Zone 8a with an average last frost of March 25. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Martin County, TX?

Martin County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 25 and first fall frost is November 12.

🌱

Your Martin County Garden Planner — Free

A 24-page printable planner built for Martin County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Martin 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.