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When to Plant Broccoli in Rockwall County, TX

Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.

Rockwall County, Texas is in USDA Zone 8a. The average last spring frost is March 9 and the first fall frost is November 20, giving you a growing season of approximately 256 days.

At an elevation of 74 feet, Rockwall County receives approximately 71.3 inches of rainfall annually with predominantly clay soil. Summer highs average 91ยฐF, providing good warmth for Broccoli during the growing season. Clay soil retains moisture well for Broccoli, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Broccoli root diseases.

Rockwall County, TX (Zone 8a) Long season
256 days
Last Spring Frost March 9
256 growing days
First Fall Frost November 20

Rockwall County Soil Profile

Soil Type

Clay

Soil pH

7.2-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (149 days to spare)
Start indoors: Jan 25 Transplant: Mar 1 🍅 Harvest: May 3 – Jun 14
Recommended (50%) ✓ Fits season (151 days to spare)
Start indoors: Feb 2 Transplant: Mar 9 🍅 Harvest: May 11 – Jun 22
Safe Start (90%) ✓ Fits season (133 days to spare)
Start indoors: Mar 6 Transplant: Apr 10 🍅 Harvest: Jun 12 – Jul 24

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Broccoli needs ~1,369 GDD — county provides 4,672 GDD Excellent fit

Broccoli Planting Timeline โ€” Rockwall County, TX

Broccoli Planting Calendar

Activity When Date Range
Start Indoors February 2 Feb 2 โ€“ Feb 16
Transplant Outdoors March 9 Mar 9 โ€“ Mar 23
Direct Sow February 23 Feb 23 โ€“ Mar 16
Fall Sowing September 11 Sep 11 โ€“ Sep 25
Harvest May 11 May 11 โ€“ Jun 22

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 8a

Growing Season

256 days

Growing Tips for Rockwall County

Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Level Up Your Garden

๐ŸŒพ Save Your Own Broccoli Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow plants to flower 2nd year; collect dry pods.
Storage Store airtight; viable 5 years at 35ยฐF, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial โ€” must overwinter roots.

Frequently Asked Questions

When should I plant Broccoli in Rockwall County, TX?

Rockwall County is in Zone 8a with an average last frost of March 9. Plan your Broccoli planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Rockwall County, TX?

Rockwall County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 9 and first fall frost is November 20.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Rockwall County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

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Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Rockwall County, TX. Local conditions may vary. Last updated: April 2026.