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

Seminole County, Florida Zone 10a May

Seminole County, Florida gardeners: here's your May plan

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

Avg. last frost February 3
Avg. first frost December 21
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Bring in the fennel (herb)

    If you can't use it all right away, check the food-preservation section of your planner.

June will be here before you know it — start on
  • 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.

Seminole County, Florida is in USDA Zone 10a. The average last spring frost is February 3 and the first fall frost is December 21, giving you a growing season of approximately 321 days.

At an elevation of 260 feet, Seminole County receives approximately 53.9 inches of rainfall annually with predominantly sand soil. Summer highs average 95°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. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Fennel (herb) root diseases.

Seminole County, FL (Zone 10a) Year-round
321 days
Last Spring Frost February 3
321 growing days
First Fall Frost December 21
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Seminole County Soil Profile

Soil Type

Sand

Soil pH

5.2-5.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (206 days to spare)
Start indoors: Dec 22 Transplant: Jan 12 🍅 Harvest: Mar 16 – May 25
Recommended (50%) ✓ Fits season (195 days to spare)
Start indoors: Jan 6 Transplant: Jan 27 🍅 Harvest: Mar 31 – Jun 9
Safe Start (90%) ✓ Fits season (172 days to spare)
Start indoors: Feb 3 Transplant: Feb 24 🍅 Harvest: Apr 28 – Jul 7

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 Seminole County

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

Soil pH

Your soil pH (5.2–5.9) overlaps with Fennel (herb)'s range (5.5–7.0), though not a perfect match.

Soil Texture

Sandy soil in Seminole 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 low (1.5%). Add 2-3 inches of compost before planting 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)

6
successive plantings in your 321-day season

Sow every 6.9 weeks. Last sowing by Sep 22 to harvest before frost.

For a dedicated fall crop, sow by Oct 26.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 2,053 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 2.9" 0" ❄️ Dormant
Feb 4.3" 3" 1.3" 💧 Light watering
Mar 4.3" 2.9" 1.4" 💧 Light watering
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 7.9" 0" ✅ Rainfall sufficient
Jul 4.3" 7.7" 0" ✅ Rainfall sufficient
Aug 4.3" 6.9" 0" ✅ Rainfall sufficient
Sep 4.3" 6.4" 0" ✅ Rainfall sufficient
Oct 4.3" 5.2" 0" ✅ Rainfall sufficient
Nov 4.3" 2.2" 2.1" 💧 Light watering
Dec 4.3" 2.2" 2.1" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Seminole 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 ~1,594 GDD — county provides 6,842 GDD Excellent fit

Fennel (herb) Planting Timeline — Seminole County, FL

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors January 6 Jan 6 – Jan 20
Transplant Outdoors January 27 Jan 27 – Feb 10
Direct Sow January 13 Jan 13 – Feb 3
Harvest March 31 Mar 31 – Jun 9
Fall Sowing October 26 Oct 26 – Nov 9

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 10a

📆 Growing Season

321 days in Seminole County

Growing Tips for Fennel (herb) in Seminole County

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

Sandy soil in Seminole 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.

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 Seminole County, FL?

Seminole County is in Zone 10a with an average last frost of February 3. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Seminole County, FL?

Seminole County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is February 3 and first fall frost is December 21.

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Your Seminole County Garden Planner — Free

A 24-page printable planner built for Seminole County (Zone 10a). 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 Seminole County, FL. 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.