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When to plant Fennel (herb) in Jersey County, IL

For Fennel (herb) in Jersey County, the safe spring window opens around March 28 and closes around April 18. Last expected frost is April 11, first fall frost October 21, giving a 193-day growing season. A second sowing from August 12 to August 26 extends the harvest into fall.

When to Plant Fennel (herb) in Jersey County, IL

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.

Jersey County, Illinois is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 21, giving you a growing season of approximately 193 days.

At an elevation of 1,202 feet, Jersey County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Fennel (herb) during the growing season.

Jersey County, IL (Zone 6b) Moderate season
193 days
Last Spring Frost April 11
193 growing days
First Fall Frost October 21

Jersey County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Fennel (herb) Planting Timeline — Jersey County, IL

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors April 4 Apr 4 – Apr 18
Direct Sow March 28 Mar 28 – Apr 18
Harvest June 6 Jun 6 – Aug 15
Fall Sowing August 12 Aug 12 – Aug 26

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6b

📆 Growing Season

193 days in Jersey County

Growing Tips for Jersey 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel (herb) in Jersey County, IL?

Jersey County is in Zone 6b with an average last frost of April 11. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jersey County, IL?

Jersey County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 11 and first fall frost is October 21.

When should I plant Fennel (herb) in Jersey County, IL?

In Jersey County, IL, plant Fennel (herb) after the last frost (around April 11) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Jersey County, IL for Fennel (herb)?

Jersey County sits in USDA Zone 6b. Fennel (herb) grows reliably in zones 4a through 10b, so it's a good fit here.

Can Fennel (herb) grow in Jersey County's climate?

Yes — Fennel (herb) grows well in Jersey County's temperate climate. Jersey County averages a 193-day frost-free season, with last frost around April 11 and first frost around October 21.

🌱

Your Jersey County Garden Planner — Free

A 22-page printable planner built for Jersey County (Zone 6b). 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 Jersey County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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