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When to Plant Fennel in Jefferson Parish, LA

Jefferson Parish, Louisiana Zone 9b May

Jefferson Parish, Louisiana gardeners: here's your May plan

Your Jefferson Parish, Louisiana garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost January 27
Avg. first frost December 18
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Harvest fennel as they ripen

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

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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.

Jefferson Parish, Louisiana is in USDA Zone 9b. The average last spring frost is January 27 and the first fall frost is December 18, giving you a growing season of approximately 325 days.

At an elevation of 314 feet, Jefferson Parish receives approximately 55.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 100°F, so Fennel may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Fennel will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Fennel root diseases.

Jefferson Parish, LA (Zone 9b) Year-round
325 days
Last Spring Frost January 27
325 growing days
First Fall Frost December 18

Jefferson Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

5-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (210 days to spare)
Start indoors: Dec 9 Transplant: Jan 27 🍅 Harvest: Mar 31 – May 12
Recommended (50%) ✓ Fits season (213 days to spare)
Start indoors: Dec 16 Transplant: Feb 3 🍅 Harvest: Apr 7 – May 19
Safe Start (90%) ✓ Fits season (184 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 Jefferson Parish

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

Soil pH

Your soil pH (5.0–6.1) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

Sandy soil in Jefferson Parish warms quickly in spring but drains fast. Fennel will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Fennel.

Organic Matter

Organic matter is low (1.7%). Add 2-3 inches of compost before planting Fennel.

How to Plant Fennel

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

Succession Planting Fennel

6
successive plantings in your 325-day season

Sow every 6.9 weeks. Last sowing by Sep 19 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.7″/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 2.6" 4.6" 0" ✅ Rainfall sufficient
Feb 2.6" 4.4" 0" ✅ Rainfall sufficient
Mar 2.6" 4.8" 0" ✅ Rainfall sufficient
Apr 2.6" 4.4" 0" ✅ Rainfall sufficient
May 2.6" 4.1" 0" ✅ Rainfall sufficient
Jun 2.6" 5.7" 0" ✅ Rainfall sufficient
Jul 2.6" 5.9" 0" ✅ Rainfall sufficient
Aug 2.6" 5.2" 0" ✅ Rainfall sufficient
Sep 2.6" 3.6" 0" ✅ Rainfall sufficient
Oct 2.6" 3.7" 0" ✅ Rainfall sufficient
Nov 2.6" 4.8" 0" ✅ Rainfall sufficient
Dec 2.6" 3.9" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Jan–Dec in Jefferson Parish). 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 ~1,875 GDD — county provides 8,150 GDD Excellent fit

Fennel Planting Timeline — Jefferson Parish, LA

Fennel Planting Calendar

Activity When Date Range
Start Indoors December 16 Dec 16 – Dec 30
Transplant Outdoors February 3 Feb 3 – Feb 17
Direct Sow January 27 Jan 27 – Feb 17
Harvest April 7 Apr 7 – May 19

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

Month-by-Month Timeline

MonthActivities
January Direct Sow
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 9b

📆 Growing Season

325 days in Jefferson Parish

Growing Tips for Fennel in Jefferson Parish

Direct sow Fennel outdoors after January 27 in Jefferson Parish when soil has warmed and frost danger has passed.

Sandy soil in Jefferson Parish dries quickly — mulch Fennel with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 100°F in Jefferson Parish, 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 Jefferson Parish, LA?

Jefferson Parish is in Zone 9b with an average last frost of January 27. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson Parish, LA?

Jefferson Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is January 27 and first fall frost is December 18.

🌱

Your Jefferson Parish Garden Planner — Free

A 24-page printable planner built for Jefferson Parish (Zone 9b). 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 Jefferson Parish, LA. 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.