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When to Plant Spinach in Williamson County, TX

Williamson County, Texas Zone 9a May

May in the garden — Williamson County, Texas

May is a pivotal month for Williamson County, Texas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost March 5
Avg. first frost November 22
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Basket week: spinach

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

June prep starts now
  • First harvests: spinach

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Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.

Williamson County, Texas is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 22, giving you a growing season of approximately 262 days.

At an elevation of 1,023 feet, Williamson County receives approximately 53.3 inches of rainfall annually with predominantly clay soil. Summer highs average 94°F, providing good warmth for Spinach during the growing season. Clay soil retains moisture well for Spinach, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Spinach root diseases.

Williamson County, TX (Zone 9a) Long season
262 days
Last Spring Frost March 5
262 growing days
First Fall Frost November 22

Williamson County Soil Profile

Soil Type

Clay

Soil pH

7.1-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (166 days to spare)
Start indoors: Jan 24 Transplant: Feb 21 🍅 Harvest: Mar 28 – May 30
Recommended (50%) ✓ Fits season (164 days to spare)
Start indoors: Feb 5 Transplant: Mar 5 🍅 Harvest: Apr 9 – Jun 11
Safe Start (90%) ✓ Fits season (152 days to spare)
Start indoors: Mar 9 Transplant: Apr 6 🍅 Harvest: May 11 – Jul 13

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 Williamson County

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

Soil pH

Your soil pH (7.1–7.8) overlaps with Spinach's range (6.5–7.5), though not a perfect match.

Soil Texture

Heavy clay soil (46% clay) in Williamson County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Drainage

Drainage is adequate for Spinach.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Spinach.

How to Plant Spinach

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 Spinach

9
successive plantings in your 262-day season

Sow every 4 weeks. Last sowing by Oct 03 to harvest before frost.

For a dedicated fall crop, sow by Sep 27.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Spinach

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

Month Spinach Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 3" 3.4" 0" ✅ Rainfall sufficient
Apr 3" 6.5" 0" ✅ Rainfall sufficient
May 3" 7.7" 0" ✅ Rainfall sufficient
Jun 3" 7.6" 0" ✅ Rainfall sufficient
Jul 3" 6.6" 0" ✅ Rainfall sufficient
Aug 3" 6.1" 0" ✅ Rainfall sufficient
Sep 3" 5.4" 0" ✅ Rainfall sufficient
Oct 3" 3.7" 0" ✅ Rainfall sufficient
Nov 3" 1.7" 1.3" 💧 Light watering
Dec 1.3" 0" ❄️ Dormant

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

Spinach 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.

Spinach needs ~871 GDD — county provides 5,371 GDD Excellent fit

Spinach Planting Timeline — Williamson County, TX

Spinach Planting Calendar

Activity When Date Range
Start Indoors February 5 Feb 5 – Feb 19
Transplant Outdoors March 5 Mar 5 – Mar 19
Direct Sow February 12 Feb 12 – Mar 5
Harvest April 9 Apr 9 – Jun 11
Fall Sowing September 27 Sep 27 – Oct 11

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

262 days in Williamson County

Growing Tips for Spinach in Williamson County

Direct sow Spinach outdoors after March 05 in Williamson County when soil has warmed and frost danger has passed.

With Williamson County's clay soil (46% clay), work in 3-4 inches of compost before planting Spinach. Avoid tilling when soil is wet to prevent compaction.

Summer highs in Williamson County reach 94°F — grow Spinach as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 262.0-day season in Williamson County allows multiple plantings of Spinach. Sow every 17.0 days for continuous harvest.

General growing tips

Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.

Recommended Spinach Varieties for Williamson County

Slow-bolting spinach for warm springs — best as fall crop here

Bloomsdale Long Standing Tyee Space

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Spinach Seeds
Life Cycle Annual
Pollination Wind Pollinated
How to Collect Let plants bolt. Harvest seed stalks when seeds turn tan.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Wind pollinated — isolate 1/2 mile for purity. Easy to let bolt in heat.

Frequently Asked Questions

When should I plant Spinach in Williamson County, TX?

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

What planting zone is Williamson County, TX?

Williamson County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 22.

🌱

Your Williamson County Garden Planner — Free

A 24-page printable planner built for Williamson 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 Williamson 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.