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When to Plant Fennel (herb) in Brazos County, TX

Brazos County, Texas Zone 9a May

Your May gardening checklist

Each item below is timed to Brazos County, Texas's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 4
Avg. first frost November 25
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Basket week: fennel (herb)

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Coming up in June — start thinking about
  • First harvests: fennel (herb)

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Herb fennel is grown for its aromatic leaves, stalks, and seeds rather than a bulb. It has a strong anise flavor and its flowers attract beneficial insects.

Brazos County, Texas is in USDA Zone 9a. The average last spring frost is March 4 and the first fall frost is November 25, giving you a growing season of approximately 266 days.

At an elevation of 74 feet, Brazos County receives approximately 63.5 inches of rainfall annually with predominantly clay soil. Summer highs average 91°F, providing good warmth for Fennel (herb) during the growing season. Clay soil retains moisture well for Fennel (herb), but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Fennel (herb) root diseases.

Brazos County, TX (Zone 9a) Long season
266 days
Last Spring Frost March 4
266 growing days
First Fall Frost November 25
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Brazos County Soil Profile

Soil Type

Clay

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (141 days to spare)
Start indoors: Jan 22 Transplant: Feb 12 🍅 Harvest: Apr 16 – Jun 25
Recommended (50%) ✓ Fits season (140 days to spare)
Start indoors: Feb 4 Transplant: Feb 25 🍅 Harvest: Apr 29 – Jul 8
Safe Start (90%) ✓ Fits season (128 days to spare)
Start indoors: Mar 8 Transplant: Mar 29 🍅 Harvest: May 31 – Aug 9

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 Brazos County

How your county's soil matches Fennel (herb)'s growing requirements.

Soil pH

Your soil pH (6.7–7.8) is more alkaline than Fennel (herb) prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (44% clay) in Brazos County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Drainage

Drainage is adequate for Fennel (herb).

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Fennel (herb).

How to Plant Fennel (herb)

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 Fennel (herb)

5
successive plantings in your 266-day season

Sow every 6.9 weeks. Last sowing by Aug 27 to harvest before frost.

For a dedicated fall crop, sow by Sep 30.

Plant Water Budget

Plant needs
1.0″/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 Fennel (herb)

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

Month Fennel (herb) Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 4.3" 3.9" 0.4" 💧 Light watering
Apr 4.3" 7.4" 0" ✅ Rainfall sufficient
May 4.3" 8.5" 0" ✅ Rainfall sufficient
Jun 4.3" 10.4" 0" ✅ Rainfall sufficient
Jul 4.3" 8.9" 0" ✅ Rainfall sufficient
Aug 4.3" 7.7" 0" ✅ Rainfall sufficient
Sep 4.3" 5.5" 0" ✅ Rainfall sufficient
Oct 4.3" 4" 0.3" 💧 Light watering
Nov 4.3" 2.2" 2.1" 💧 Light watering
Dec 1.4" 0" ❄️ Dormant

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

Fennel (herb) 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.

Fennel (herb) needs ~1,369 GDD — county provides 4,854 GDD Excellent fit

Fennel (herb) Planting Timeline — Brazos County, TX

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors February 4 Feb 4 – Feb 18
Transplant Outdoors February 25 Feb 25 – Mar 11
Direct Sow February 11 Feb 11 – Mar 4
Harvest April 29 Apr 29 – Jul 8
Fall Sowing September 30 Sep 30 – Oct 14

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

266 days in Brazos County

Growing Tips for Fennel (herb) in Brazos County

Direct sow Fennel (herb) outdoors after March 04 in Brazos County when soil has warmed and frost danger has passed.

With Brazos County's clay soil (44% clay), work in 3-4 inches of compost before planting Fennel (herb). Avoid tilling when soil is wet to prevent compaction.

Common pests for Fennel (herb) in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Unlike Florence fennel, herb fennel does not form a bulb. Harvest fronds as needed and seeds when they turn brown. Self-sows readily.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel (herb) in Brazos County, TX?

Brazos County is in Zone 9a with an average last frost of March 4. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Brazos County, TX?

Brazos County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 4 and first fall frost is November 25.

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Your Brazos County Garden Planner — Free

A 24-page printable planner built for Brazos 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 Brazos 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.