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When to Plant Fennel (herb) in Mobile County, AL

Mobile County, Alabama Zone 9a May

Your May planting checklist for Mobile County, Alabama

Welcome to May in Zone 9a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 3
Avg. first frost November 24
Soil temp (4") 71°F
Watering Moderate
Pest pressure High
Daylight 13.6 hrs
  1. Pick fennel (herb)

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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  • 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.

Mobile County, Alabama is in USDA Zone 9a. The average last spring frost is March 3 and the first fall frost is November 24, giving you a growing season of approximately 266 days.

At an elevation of 101 feet, Mobile County receives approximately 48.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Fennel (herb) may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Fennel (herb) will need more frequent watering and organic matter to retain nutrients.

Mobile County, AL (Zone 9a) Long season
266 days
Last Spring Frost March 3
266 growing days
First Fall Frost November 24

Mobile County Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (145 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 3 Transplant: Feb 24 🍅 Harvest: Apr 28 – Jul 7
Safe Start (90%) ✓ Fits season (140 days to spare)
Start indoors: Feb 20 Transplant: Mar 13 🍅 Harvest: May 15 – Jul 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 Mobile County

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

Soil pH

Your soil pH (4.8–6.1) is more acidic than Fennel (herb) prefers (5.5–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Mobile County warms quickly in spring but drains fast. Fennel (herb) will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Fennel (herb).

Organic Matter

Organic matter is moderate (2.2%). 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 26 to harvest before frost.

For a dedicated fall crop, sow by Sep 29.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 3.7" 0" ❄️ Dormant
Feb 3.5" 0" ❄️ Dormant
Mar 4.3" 4.9" 0" ✅ Rainfall sufficient
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 5.5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 4.3" 4.3" 0" ✅ Rainfall sufficient
Dec 4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Mobile 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 ~1,706 GDD — county provides 6,051 GDD Excellent fit

Fennel (herb) Planting Timeline — Mobile County, AL

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors February 3 Feb 3 – Feb 17
Transplant Outdoors February 24 Feb 24 – Mar 10
Direct Sow February 10 Feb 10 – Mar 3
Harvest April 28 Apr 28 – Jul 7
Fall Sowing September 29 Sep 29 – Oct 13

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

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_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

266 days in Mobile County

Growing Tips for Fennel (herb) in Mobile County

Direct sow Fennel (herb) outdoors after March 03 in Mobile County when soil has warmed and frost danger has passed.

Sandy soil in Mobile County dries quickly — mulch Fennel (herb) with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 97°F in Mobile 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 Mobile County, AL?

Mobile County is in Zone 9a with an average last frost of March 3. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mobile County, AL?

Mobile County, Alabama is in USDA Hardiness Zone 9a. The average last spring frost is March 3 and first fall frost is November 24.

🌱

Your Mobile County Garden Planner — Free

A 24-page printable planner built for Mobile 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 Mobile County, AL. 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.