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When to Plant Broccoli Rabe in Williamson County, TX

Williamson County, Texas Zone 9a May

May in Williamson County, Texas — your action list

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

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. Bring in the broccoli rabe

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

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Broccoli rabe (rapini) is a brassica grown for its slightly bitter, nutty-flavored florets, leaves, and stems. It is a staple in Italian cooking.

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 Broccoli Rabe during the growing season. Clay soil retains moisture well for Broccoli Rabe, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Broccoli Rabe 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 (187 days to spare)
Start indoors: Jan 24 Transplant: Feb 21 🍅 Harvest: Apr 4 – May 9
Recommended (50%) ✓ Fits season (185 days to spare)
Start indoors: Feb 5 Transplant: Mar 5 🍅 Harvest: Apr 16 – May 21
Safe Start (90%) ✓ Fits season (173 days to spare)
Start indoors: Mar 9 Transplant: Apr 6 🍅 Harvest: May 18 – Jun 22

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 Broccoli Rabe's growing requirements.

Soil pH

Your soil pH (7.1–7.8) overlaps with Broccoli Rabe's range (6.0–7.5), 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 Broccoli Rabe.

Organic Matter

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

How to Plant Broccoli Rabe

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Succession Planting Broccoli Rabe

7
successive plantings in your 262-day season

Sow every 4.6 weeks. Last sowing by Sep 23 to harvest before frost.

For a dedicated fall crop, sow by Sep 27.

Plant Water Budget

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

Monthly Watering Guide for Broccoli Rabe

Broccoli Rabe needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Broccoli Rabe Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 3.5" 3.4" 0.1" 💧 Light watering
Apr 3.5" 6.5" 0" ✅ Rainfall sufficient
May 3.5" 7.7" 0" ✅ Rainfall sufficient
Jun 3.5" 7.6" 0" ✅ Rainfall sufficient
Jul 3.5" 6.6" 0" ✅ Rainfall sufficient
Aug 3.5" 6.1" 0" ✅ Rainfall sufficient
Sep 3.5" 5.4" 0" ✅ Rainfall sufficient
Oct 3.5" 3.7" 0" ✅ Rainfall sufficient
Nov 3.5" 1.7" 1.8" 🚿 Regular 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.

Broccoli Rabe 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.

Broccoli Rabe needs ~1,025 GDD — county provides 5,371 GDD Excellent fit

Broccoli Rabe Planting Timeline — Williamson County, TX

Broccoli Rabe 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 16 Apr 16 – May 21
Fall Sowing September 27 Sep 27 – Oct 11

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

262 days in Williamson County

Growing Tips for Broccoli Rabe in Williamson County

Direct sow Broccoli Rabe 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 Broccoli Rabe. Avoid tilling when soil is wet to prevent compaction.

Your generous 262.0-day season in Williamson County allows multiple plantings of Broccoli Rabe. Sow every 20.0 days for continuous harvest.

Common pests for Broccoli Rabe in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Harvest when small yellow flower buds first appear but before they open. Cut the main shoot first to encourage side shoots.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Broccoli Rabe in Williamson County, TX?

Williamson County is in Zone 9a with an average last frost of March 5. Plan your Broccoli Rabe 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.