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When to Plant Fennel in Somervell County, TX

Somervell County, Texas Zone 8b May

May to-do list for Somervell County, Texas

May is a pivotal month for Somervell County, Texas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost March 19
Avg. first frost November 12
Soil temp (4") 56°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
  1. Start fennel indoors

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

June prep starts now
  • First harvests: fennel

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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.

Somervell County, Texas is in USDA Zone 8b. The average last spring frost is March 19 and the first fall frost is November 12, giving you a growing season of approximately 238 days.

At an elevation of 4,773 feet, Somervell County receives approximately 64.7 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, 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.

Somervell County, TX (Zone 8b) Long season
238 days
Last Spring Frost March 19
238 growing days
First Fall Frost November 12

Somervell County Soil Profile

Soil Type

Clay

Soil pH

7.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (127 days to spare)
Start indoors: Jan 18 Transplant: Mar 22 🍅 Harvest: May 24 – Jul 5
Recommended (50%) ✓ Fits season (119 days to spare)
Start indoors: Jan 29 Transplant: Apr 2 🍅 Harvest: Jun 4 – Jul 16
Safe Start (90%) ✓ Fits season (112 days to spare)
Start indoors: Feb 22 Transplant: Apr 26 🍅 Harvest: Jun 28 – 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 Somervell County

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

Soil pH

Your soil pH (7.2–7.8) is more alkaline than Fennel prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (46% clay) in Somervell County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (3.3%). Annual compost additions will help Fennel.

How to Plant Fennel

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

Succession Planting Fennel

4
successive plantings in your 238-day season

Sow every 6.9 weeks. Last sowing by Aug 14 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
1.1″/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 1.8" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 2.6" 4.3" 0" ✅ Rainfall sufficient
Apr 2.6" 6.9" 0" ✅ Rainfall sufficient
May 2.6" 10.2" 0" ✅ Rainfall sufficient
Jun 2.6" 10.5" 0" ✅ Rainfall sufficient
Jul 2.6" 7.5" 0" ✅ Rainfall sufficient
Aug 2.6" 7.8" 0" ✅ Rainfall sufficient
Sep 2.6" 5.4" 0" ✅ Rainfall sufficient
Oct 2.6" 3.8" 0" ✅ Rainfall sufficient
Nov 2.6" 2.4" 0.2" 💧 Light watering
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Somervell 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 ~1,312 GDD — county provides 4,165 GDD Excellent fit

Fennel Planting Timeline — Somervell County, TX

Fennel Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors April 2 Apr 2 – Apr 16
Direct Sow March 26 Mar 26 – Apr 16
Harvest June 4 Jun 4 – Jul 16

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

Month-by-Month Timeline

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

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: too_alkaline

🗺️ USDA Zone

Zone 8b

📆 Growing Season

238 days in Somervell County

Growing Tips for Fennel in Somervell County

Direct sow Fennel outdoors after March 19 in Somervell County when soil has warmed and frost danger has passed.

With Somervell County's clay soil (46% 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 Somervell County, TX?

Somervell County is in Zone 8b with an average last frost of March 19. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Somervell County, TX?

Somervell County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 19 and first fall frost is November 12.

🌱

Your Somervell County Garden Planner — Free

A 24-page printable planner built for Somervell County (Zone 8b). 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 Somervell 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.