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When to Plant Broccoli in Harris County, TX

Harris County, Texas Zone 9b May

Top priorities for Harris County, Texas gardeners in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Harris County, Texas.

Avg. last frost February 14
Avg. first frost December 4
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Harvest broccoli as they ripen

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

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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.

Harris County, Texas is in USDA Zone 9b. The average last spring frost is February 14 and the first fall frost is December 4, giving you a growing season of approximately 293 days.

At an elevation of 390 feet, Harris County receives approximately 67.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 102°F, so Broccoli may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Broccoli will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Broccoli root diseases.

Harris County, TX (Zone 9b) Year-round
293 days
Last Spring Frost February 14
293 growing days
First Fall Frost December 4

Harris County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (188 days to spare)
Start indoors: Jan 9 Transplant: Feb 6 🍅 Harvest: Apr 10 – May 22
Recommended (50%) ✓ Fits season (188 days to spare)
Start indoors: Jan 17 Transplant: Feb 14 🍅 Harvest: Apr 18 – May 30
Safe Start (90%) ✓ Fits season (184 days to spare)
Start indoors: Feb 8 Transplant: Mar 8 🍅 Harvest: May 10 – Jun 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 Harris County

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

Soil pH

Your soil pH (5.3–6.5) is more acidic than Broccoli prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Broccoli.

How to Plant Broccoli

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

5
successive plantings in your 293-day season

Sow every 6.9 weeks. Last sowing by Sep 05 to harvest before frost.

For a dedicated fall crop, sow by Oct 09.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 86 gal / 100 sq ft

Monthly Watering Guide for Broccoli

Broccoli needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Broccoli Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 4.3" 2.7" 1.6" 💧 Light watering
Mar 4.3" 3.8" 0.5" 💧 Light watering
Apr 4.3" 7.4" 0" ✅ Rainfall sufficient
May 4.3" 10.1" 0" ✅ Rainfall sufficient
Jun 4.3" 10" 0" ✅ Rainfall sufficient
Jul 4.3" 9.6" 0" ✅ Rainfall sufficient
Aug 4.3" 8.5" 0" ✅ Rainfall sufficient
Sep 4.3" 6.3" 0" ✅ Rainfall sufficient
Oct 4.3" 3.9" 0.4" 💧 Light watering
Nov 4.3" 2.2" 2.1" 💧 Light watering
Dec 4.3" 1.6" 2.7" 🚿 Regular watering

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

Broccoli 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 needs ~1,988 GDD — county provides 7,791 GDD Excellent fit

Broccoli Planting Timeline — Harris County, TX

Broccoli Planting Calendar

Activity When Date Range
Start Indoors January 17 Jan 17 – Jan 31
Transplant Outdoors February 14 Feb 14 – Feb 28
Direct Sow January 24 Jan 24 – Feb 14
Harvest April 18 Apr 18 – May 30
Fall Sowing October 9 Oct 9 – Oct 23

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

293 days in Harris County

Growing Tips for Broccoli in Harris County

Direct sow Broccoli outdoors after February 14 in Harris County when soil has warmed and frost danger has passed.

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

Summer highs in Harris County reach 102°F — grow Broccoli as a spring or fall crop. Use shade cloth if planting in summer.

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

General growing tips

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

Recommended Broccoli Varieties for Harris County

Heat-tolerant broccoli — plant as early spring or fall crop

Arcadia Marathon Green Magic

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

🌾 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 35°F, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial — must overwinter roots.

Frequently Asked Questions

When should I plant Broccoli in Harris County, TX?

Harris County is in Zone 9b with an average last frost of February 14. Plan your Broccoli planting based on this frost date — see the calendar above for exact timing.

What planting zone is Harris County, TX?

Harris County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 14 and first fall frost is December 4.

🌱

Your Harris County Garden Planner — Free

A 24-page printable planner built for Harris County (Zone 9b). 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 Harris 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.