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When to Plant Fennel in Willacy County, TX

Willacy County, Texas Zone 10a May

Top priorities for Willacy 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 Willacy County, Texas.

Avg. last frost February 4
Avg. first frost December 22
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 13.3 hrs
  1. It's harvest week for fennel

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

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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.

Willacy County, Texas is in USDA Zone 10a. The average last spring frost is February 4 and the first fall frost is December 22, giving you a growing season of approximately 321 days.

At an elevation of 1,085 feet, Willacy County receives approximately 65.9 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Fennel may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Fennel root diseases.

Willacy County, TX (Zone 10a) Year-round
321 days
Last Spring Frost February 4
321 growing days
First Fall Frost December 22

Willacy County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (221 days to spare)
Start indoors: Dec 6 Transplant: Jan 24 🍅 Harvest: Mar 28 – May 9
Recommended (50%) ✓ Fits season (209 days to spare)
Start indoors: Dec 24 Transplant: Feb 11 🍅 Harvest: Apr 15 – May 27
Safe Start (90%) ✓ Fits season (186 days to spare)
Start indoors: Jan 21 Transplant: Mar 11 🍅 Harvest: May 13 – Jun 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.

Soil Compatibility in Willacy County

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

Soil pH

Your soil pH (6.5–7.3) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Fennel.

Organic Matter

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

How to Plant Fennel

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

Succession Planting Fennel

6
successive plantings in your 321-day season

Sow every 6.9 weeks. Last sowing by Sep 23 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.9″/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

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 1.7" 0" ❄️ Dormant
Feb 2.6" 2.3" 0.3" 💧 Light watering
Mar 2.6" 4.4" 0" ✅ Rainfall sufficient
Apr 2.6" 6.4" 0" ✅ Rainfall sufficient
May 2.6" 9.5" 0" ✅ Rainfall sufficient
Jun 2.6" 9.7" 0" ✅ Rainfall sufficient
Jul 2.6" 9" 0" ✅ Rainfall sufficient
Aug 2.6" 8.5" 0" ✅ Rainfall sufficient
Sep 2.6" 6.3" 0" ✅ Rainfall sufficient
Oct 2.6" 3.8" 0" ✅ Rainfall sufficient
Nov 2.6" 2.6" 0" ✅ Rainfall sufficient
Dec 2.6" 1.8" 0.8" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Willacy County). Supplement amounts are based on average rainfall — 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" — 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 needs ~1,988 GDD — county provides 8,533 GDD Excellent fit

Fennel Planting Timeline — Willacy County, TX

Fennel Planting Calendar

Activity When Date Range
Start Indoors December 24 Dec 24 – Jan 7
Transplant Outdoors February 11 Feb 11 – Feb 25
Direct Sow February 4 Feb 4 – Feb 25
Harvest April 15 Apr 15 – May 27

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 10a

📆 Growing Season

321 days in Willacy County

Growing Tips for Fennel in Willacy County

Direct sow Fennel outdoors after February 04 in Willacy County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Willacy County, provide afternoon shade for Fennel and water deeply in the morning.

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 Willacy County, TX?

Willacy County is in Zone 10a with an average last frost of February 4. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Willacy County, TX?

Willacy County, Texas is in USDA Hardiness Zone 10a. The average last spring frost is February 4 and first fall frost is December 22.

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Your Willacy County Garden Planner — Free

A 24-page printable planner built for Willacy County (Zone 10a). 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 Willacy 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.