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

Brown County, Texas Zone 8a May

What to do in May

Here's what deserves your attention in Brown County, Texas this month. Everything below is tailored to Zone 8a and timed around your local frost dates.

Avg. last frost March 22
Avg. first frost November 14
Soil temp (4") 60°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Pick fennel (herb)

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

A few tasks this May that'll pay off in June
  • 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.

Brown County, Texas is in USDA Zone 8a. The average last spring frost is March 22 and the first fall frost is November 14, giving you a growing season of approximately 237 days.

At an elevation of 4,423 feet, Brown County receives approximately 55.4 inches of rainfall annually with predominantly loam soil. Summer highs average 96°F, so Fennel (herb) may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Fennel (herb) root diseases.

Brown County, TX (Zone 8a) Long season
237 days
Last Spring Frost March 22
237 growing days
First Fall Frost November 14

Brown County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (112 days to spare)
Start indoors: Feb 2 Transplant: Mar 2 🍅 Harvest: May 4 – Jul 13
Recommended (50%) ✓ Fits season (111 days to spare)
Start indoors: Feb 15 Transplant: Mar 15 🍅 Harvest: May 17 – Jul 26
Safe Start (90%) ✓ Fits season (109 days to spare)
Start indoors: Mar 9 Transplant: Apr 6 🍅 Harvest: Jun 8 – Aug 17

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 Brown County

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

Soil pH

Your soil pH (6.8–7.5) is more alkaline than Fennel (herb) prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Brown County is excellent for Fennel (herb) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Fennel (herb).

How to Plant Fennel (herb)

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Fennel (herb)

4
successive plantings in your 237-day season

Sow every 6.9 weeks. Last sowing by Aug 16 to harvest before frost.

For a dedicated fall crop, sow by Sep 05.

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 38 gal / 100 sq ft

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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 4.3" 3.8" 0.5" 💧 Light watering
Apr 4.3" 5.9" 0" ✅ Rainfall sufficient
May 4.3" 7.8" 0" ✅ Rainfall sufficient
Jun 4.3" 8.3" 0" ✅ Rainfall sufficient
Jul 4.3" 7.4" 0" ✅ Rainfall sufficient
Aug 4.3" 7.3" 0" ✅ Rainfall sufficient
Sep 4.3" 5.4" 0" ✅ Rainfall sufficient
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 1.7" 2.6" 🚿 Regular watering
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Brown 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 ~1,650 GDD — county provides 5,214 GDD Excellent fit

Fennel (herb) Planting Timeline — Brown County, TX

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors February 15 Feb 15 – Mar 1
Transplant Outdoors March 15 Mar 15 – Mar 29
Direct Sow March 8 Mar 8 – Mar 29
Harvest May 17 May 17 – Jul 26
Fall Sowing September 5 Sep 5 – Sep 19

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
April
May Harvest
June Harvest
July Harvest
August
September Fall Sowing
October
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 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8a

📆 Growing Season

237 days in Brown County

Growing Tips for Fennel (herb) in Brown County

Direct sow Fennel (herb) outdoors after March 22 in Brown County when soil has warmed and frost danger has passed.

With summer highs reaching 96°F in Brown County, provide afternoon shade for Fennel (herb) and water deeply in the morning.

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 Brown County, TX?

Brown County is in Zone 8a with an average last frost of March 22. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Brown County, TX?

Brown County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 22 and first fall frost is November 14.

🌱

Your Brown County Garden Planner — Free

A 24-page printable planner built for Brown County (Zone 8a). 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 Brown 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.