Blog

When to Plant Tomatoes in Grimes County, TX

Grimes County, Texas Zone 9a May

Top priorities for Grimes County, Texas gardeners in May

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

Avg. last frost February 25
Avg. first frost December 1
Soil temp (4") 73°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

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.

Grimes County, Texas is in USDA Zone 9a. The average last spring frost is February 25 and the first fall frost is December 1, giving you a growing season of approximately 279 days.

At an elevation of 33 feet, Grimes County receives approximately 65.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 91°F, providing good warmth for Tomatoes during the growing season. 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.

Grimes County, TX (Zone 9a) Year-round
279 days
Last Spring Frost February 25
279 growing days
First Fall Frost December 1

Grimes County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.8-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (143 days to spare)
Start indoors: Jan 1 Transplant: Feb 19 🍅 Harvest: Apr 23 – Jul 2
Recommended (50%) ✓ Fits season (139 days to spare)
Start indoors: Jan 14 Transplant: Mar 4 🍅 Harvest: May 6 – Jul 15
Safe Start (90%) ✓ Fits season (142 days to spare)
Start indoors: Jan 28 Transplant: Mar 18 🍅 Harvest: May 20 – Jul 29

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 Grimes County

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

Soil pH

Your soil pH (5.8–6.5) overlaps with Tomatoes's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Tomatoes.

Organic Matter

Organic matter is low (1.7%). 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

5
successive plantings in your 279-day season

Sow every 6.9 weeks. Last sowing by Sep 07 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
1.0″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,740 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 1.9" 0" ❄️ Dormant
Feb 5.2" 2.1" 3.1" 🚿 Regular watering
Mar 5.2" 4.7" 0.5" 💧 Light watering
Apr 5.2" 6" 0" ✅ Rainfall sufficient
May 5.2" 9.9" 0" ✅ Rainfall sufficient
Jun 5.2" 9.9" 0" ✅ Rainfall sufficient
Jul 5.2" 8.3" 0" ✅ Rainfall sufficient
Aug 5.2" 8.3" 0" ✅ Rainfall sufficient
Sep 5.2" 6.6" 0" ✅ Rainfall sufficient
Oct 5.2" 3.9" 1.3" 💧 Light watering
Nov 5.2" 2" 3.2" 🚿 Regular watering
Dec 5.2" 1.7" 3.5" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Grimes 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 ~1,323 GDD — county provides 5,110 GDD Excellent fit

Tomatoes Planting Timeline — Grimes County, TX

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors January 14 Jan 14 – Jan 28
Transplant Outdoors March 4 Mar 4 – Mar 18
Direct Sow February 25 Feb 25 – Mar 18
Harvest May 6 May 6 – Jul 15

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 · 1-2 times/week

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

279 days in Grimes County

Growing Tips for Tomatoes in Grimes County

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

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

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 Grimes 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 Grimes County, TX?

Grimes County is in Zone 9a with an average last frost of February 25. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grimes County, TX?

Grimes County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 25 and first fall frost is December 1.

🌱

Your Grimes County Garden Planner — Free

A 24-page printable planner built for Grimes 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.

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 Grimes 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.