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When to Plant Fennel (herb) in Pinellas County, FL

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.

Pinellas County, Florida is in USDA Zone 9b. The average last spring frost is January 25 and the first fall frost is December 16, giving you a growing season of approximately 325 days.

At an elevation of 246 feet, Pinellas County receives approximately 58.1 inches of rainfall annually with predominantly sand soil. Summer highs average 102ยฐF, 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.

Pinellas County, FL (Zone 9b) Year-round
325 days
Last Spring Frost January 25
325 growing days
First Fall Frost December 16

Pinellas County Soil Profile

Soil Type

Sand

Soil pH

5.1-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (199 days to spare)
Start indoors: Dec 22 Transplant: Jan 12 🍅 Harvest: Mar 16 – May 25
Recommended (50%) ✓ Fits season (199 days to spare)
Start indoors: Dec 28 Transplant: Jan 18 🍅 Harvest: Mar 22 – May 31
Safe Start (90%) ✓ Fits season (173 days to spare)
Start indoors: Jan 31 Transplant: Feb 21 🍅 Harvest: Apr 25 – Jul 4

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
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,600 gal / 100 sq ft
Fennel (herb) needs ~1,988 GDD — county provides 8,639 GDD Excellent fit

Fennel (herb) Planting Timeline โ€” Pinellas County, FL

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors December 28 Dec 28 โ€“ Jan 11
Transplant Outdoors January 18 Jan 18 โ€“ Feb 1
Direct Sow January 4 Jan 4 โ€“ Jan 25
Fall Sowing October 21 Oct 21 โ€“ Nov 4
Harvest March 22 Mar 22 โ€“ May 31

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

Month-by-Month Timeline

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

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 9b

Growing Season

325 days

Growing Tips for Pinellas County

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

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Frequently Asked Questions

When should I plant Fennel (herb) in Pinellas County, FL?

Pinellas County is in Zone 9b with an average last frost of January 25. Plan your Fennel (herb) planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Pinellas County, FL?

Pinellas County, Florida is in USDA Hardiness Zone 9b. The average last spring frost is January 25 and first fall frost is December 16.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Pinellas County gardeners in Zone 9b 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 Pinellas County, FL. Local conditions may vary. Last updated: April 2026.