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

Plant Fennel (herb) in Kendall County, when soil hits 50°F — usually April 6. Continue planting through April 27 for the spring crop. A second sowing from August 8 to August 22 extends the harvest into fall.

When to Plant Fennel (herb) in Kendall 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.

Kendall County, Illinois is in USDA Zone 5b. The average last spring frost is April 20 and the first fall frost is October 17, giving you a growing season of approximately 180 days.

At an elevation of 708 feet, Kendall County receives approximately 38.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Fennel (herb) during the growing season.

Kendall County, IL (Zone 5b) Moderate season
180 days
Last Spring Frost April 20
180 growing days
First Fall Frost October 17

Kendall County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Fennel (herb) Planting Timeline — Kendall County, IL

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow April 6 Apr 6 – Apr 27
Harvest June 15 Jun 15 – Aug 24
Fall Sowing August 8 Aug 8 – Aug 22

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
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 5b

📆 Growing Season

180 days in Kendall County

Growing Tips for Kendall 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 Kendall County, IL?

Kendall County is in Zone 5b with an average last frost of April 20. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kendall County, IL?

Kendall County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 20 and first fall frost is October 17.

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

In Kendall County, IL, plant Fennel (herb) after the last frost (around April 20) and before the first frost (around October 17). Best results when soil holds above 50°F.

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

Kendall County sits in USDA Zone 5b. Fennel (herb) grows reliably in zones 4a through 10b, so it's a good fit here.

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

Yes — Fennel (herb) grows well in Kendall County's temperate climate. Kendall County averages a 180-day frost-free season, with last frost around April 20 and first frost around October 17.

🌱

Your Kendall County Garden Planner — Free

A 22-page printable planner built for Kendall County (Zone 5b). 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 Kendall County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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