Blog

When to Plant Lettuce in Robertson County, TX

Robertson County, Texas Zone 9a May

Top priorities for Robertson County, Texas gardeners in May

Here's what deserves your attention in Robertson County, Texas this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost March 7
Avg. first frost November 16
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Pick lettuce

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

June prep starts now
  • First harvests: lettuce

Instant PDF download. No spam, unsubscribe any time.

Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.

Robertson County, Texas is in USDA Zone 9a. The average last spring frost is March 7 and the first fall frost is November 16, giving you a growing season of approximately 254 days.

At an elevation of 85 feet, Robertson County receives approximately 61.1 inches of rainfall annually with predominantly clay soil. Summer highs average 93°F, providing good warmth for Lettuce during the growing season. Clay soil retains moisture well for Lettuce, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Lettuce root diseases.

Robertson County, TX (Zone 9a) Long season
254 days
Last Spring Frost March 7
254 growing days
First Fall Frost November 16
Share this guide:

Robertson County Soil Profile

Soil Type

Clay

Soil pH

6.8-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (151 days to spare)
Start indoors: Jan 31 Transplant: Feb 28 🍅 Harvest: Apr 4 – Jun 13
Recommended (50%) ✓ Fits season (149 days to spare)
Start indoors: Feb 7 Transplant: Mar 7 🍅 Harvest: Apr 11 – Jun 20
Safe Start (90%) ✓ Fits season (143 days to spare)
Start indoors: Mar 10 Transplant: Apr 7 🍅 Harvest: May 12 – Jul 21

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 Robertson County

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

Soil pH

Your soil pH (6.8–8.0) is more alkaline than Lettuce prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (45% clay) in Robertson County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Lettuce.

How to Plant Lettuce

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Lettuce

10
successive plantings in your 254-day season

Sow every 3.4 weeks. Last sowing by Sep 17 to harvest before frost.

For a dedicated fall crop, sow by Sep 21.

Plant Water Budget

Plant needs
0.7″/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 Lettuce

Lettuce needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Lettuce Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 3" 4.3" 0" ✅ Rainfall sufficient
Apr 3" 5.6" 0" ✅ Rainfall sufficient
May 3" 10" 0" ✅ Rainfall sufficient
Jun 3" 8.4" 0" ✅ Rainfall sufficient
Jul 3" 8.3" 0" ✅ Rainfall sufficient
Aug 3" 8.2" 0" ✅ Rainfall sufficient
Sep 3" 5.2" 0" ✅ Rainfall sufficient
Oct 3" 3.7" 0" ✅ Rainfall sufficient
Nov 3" 2.3" 0.7" 💧 Light watering
Dec 1.6" 0" ❄️ Dormant

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

Lettuce 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.

Lettuce needs ~889 GDD — county provides 5,016 GDD Excellent fit

Lettuce Planting Timeline — Robertson County, TX

Lettuce Planting Calendar

Activity When Date Range
Start Indoors February 7 Feb 7 – Feb 21
Transplant Outdoors March 7 Mar 7 – Mar 21
Direct Sow February 14 Feb 14 – Mar 7
Harvest April 11 Apr 11 – Jun 20
Fall Sowing September 21 Sep 21 – Oct 5

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors Direct Sow
March Transplant Outdoors Direct Sow
April Harvest
May Harvest
June Harvest
July
August
September Fall Sowing
October Fall Sowing
November
December
Share this guide:

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

30–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

254 days in Robertson County

Growing Tips for Lettuce in Robertson County

Direct sow Lettuce outdoors after March 07 in Robertson County when soil has warmed and frost danger has passed.

With Robertson County's clay soil (45% clay), work in 3-4 inches of compost before planting Lettuce. Avoid tilling when soil is wet to prevent compaction.

Summer highs in Robertson County reach 93°F — grow Lettuce as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 254.0-day season in Robertson County allows multiple plantings of Lettuce. Sow every 15.0 days for continuous harvest.

Common pests for Lettuce in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.

Recommended Lettuce Varieties for Robertson County

Bolt-resistant varieties for warm summers — grow as spring/fall crop

Jericho Muir Nevada New Red Fire

Companion Planting

Good Companions

Avoid Planting Near

  • Celery

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Lettuce Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let plants bolt and flower. Harvest seed heads when fluffy.
Storage Store airtight; viable 6 years at 35°F, under 45% humidity.

Very easy to save. Let a few plants bolt each season.

Frequently Asked Questions

When should I plant Lettuce in Robertson County, TX?

Robertson County is in Zone 9a with an average last frost of March 7. Plan your Lettuce planting based on this frost date — see the calendar above for exact timing.

What planting zone is Robertson County, TX?

Robertson County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 7 and first fall frost is November 16.

🌱

Your Robertson County Garden Planner — Free

A 24-page printable planner built for Robertson 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 Robertson 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.