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When to Plant Fennel in Brazos County, TX

Florence fennel is grown for its swollen bulb-like stem base, which has a mild anise flavor. It is crisp raw in salads and sweet when roasted or braised.

Brazos County, Texas is in USDA Zone 8b. 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 91ยฐF, providing good warmth for Fennel during the growing season. Clay soil retains moisture well for Fennel, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Fennel root diseases.

Brazos County, TX (Zone 8b) Long season
266 days
Last Spring Frost March 4
266 growing days
First Fall Frost November 25

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 (148 days to spare)
Start indoors: Jan 1 Transplant: Mar 5 🍅 Harvest: May 7 – Jun 18
Recommended (50%) ✓ Fits season (147 days to spare)
Start indoors: Jan 14 Transplant: Mar 18 🍅 Harvest: May 20 – Jul 1
Safe Start (90%) ✓ Fits season (135 days to spare)
Start indoors: Feb 15 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 2

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's growing requirements.

Soil pH

Your soil pH (6.7โ€“7.8) is more alkaline than Fennel prefers (5.5โ€“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.

Organic Matter

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

How to Plant Fennel

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

Succession Planting Fennel

5
successive plantings in your 266-day season

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

Plant Water Budget

Plant needs
0.6″/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 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Fennel

Fennel needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Fennel Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 2.2" 0" โ„๏ธ Dormant
Mar 2.6" 3.9" 0" โœ… Rainfall sufficient
Apr 2.6" 7.4" 0" โœ… Rainfall sufficient
May 2.6" 8.5" 0" โœ… Rainfall sufficient
Jun 2.6" 10.4" 0" โœ… Rainfall sufficient
Jul 2.6" 8.9" 0" โœ… Rainfall sufficient
Aug 2.6" 7.7" 0" โœ… Rainfall sufficient
Sep 2.6" 5.5" 0" โœ… Rainfall sufficient
Oct 2.6" 4" 0" โœ… Rainfall sufficient
Nov 2.6" 2.2" 0.4" ๐Ÿ’ง Light watering
Dec โ€” 1.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Brazos County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Fennel 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" โ€” every day above 50ยฐF 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 needs ~1,369 GDD — county provides 4,854 GDD Excellent fit

Fennel Planting Timeline โ€” Brazos County, TX

Fennel Planting Calendar

Activity When Date Range
Start Indoors January 14 Jan 14 โ€“ Jan 28
Transplant Outdoors March 18 Mar 18 โ€“ Apr 1
Direct Sow March 11 Mar 11 โ€“ Apr 1
Harvest May 20 May 20 โ€“ Jul 1

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.6"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 8b

๐Ÿ“† Growing Season

266 days in Brazos County

Growing Tips for Fennel in Brazos County

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

Common pests for Fennel 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 late summer for fall harvest to reduce bolting. Hill soil around bulbs as they enlarge. Harvest when bulbs are tennis-ball sized before they elongate.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel in Brazos County, TX?

Brazos County is in Zone 8b with an average last frost of March 4. Plan your Fennel planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Brazos County, TX?

Brazos County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 4 and first fall frost is November 25.

๐ŸŒฑ

Plan Your Garden with Confidence

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

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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: April 2026.