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When to Plant Fennel (herb) in St. Charles Parish, LA

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.

St. Charles Parish, Louisiana is in USDA Zone 9a. The average last spring frost is February 20 and the first fall frost is December 1, giving you a growing season of approximately 284 days.

At an elevation of 154 feet, St. Charles Parish receives approximately 54.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 103ยฐF, so Fennel (herb) may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Fennel (herb) will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Fennel (herb) root diseases.

St. Charles Parish, LA (Zone 9a) Year-round
284 days
Last Spring Frost February 20
284 growing days
First Fall Frost December 1

St. Charles Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.9-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (162 days to spare)
Start indoors: Jan 9 Transplant: Jan 30 🍅 Harvest: Apr 3 – Jun 12
Recommended (50%) ✓ Fits season (158 days to spare)
Start indoors: Jan 23 Transplant: Feb 13 🍅 Harvest: Apr 17 – Jun 26
Safe Start (90%) ✓ Fits season (145 days to spare)
Start indoors: Feb 22 Transplant: Mar 15 🍅 Harvest: May 17 – Jul 26

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.

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
Fennel (herb) needs ~2,044 GDD — county provides 7,766 GDD Excellent fit

Fennel (herb) Planting Timeline โ€” St. Charles Parish, LA

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 โ€“ Feb 6
Transplant Outdoors February 13 Feb 13 โ€“ Feb 27
Direct Sow January 30 Jan 30 โ€“ Feb 20
Fall Sowing October 6 Oct 6 โ€“ Oct 20
Harvest April 17 Apr 17 โ€“ Jun 26

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 9a

Growing Season

284 days

Growing Tips for St. Charles Parish

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Fennel (herb) in St. Charles Parish, LA?

St. Charles Parish is in Zone 9a with an average last frost of February 20. Plan your Fennel (herb) planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is St. Charles Parish, LA?

St. Charles Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is February 20 and first fall frost is December 1.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help St. Charles Parish gardeners in Zone 9a 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 St. Charles Parish, LA. Local conditions may vary. Last updated: April 2026.