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When to Plant Fennel (herb) in Pope 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.

Pope County, Illinois is in USDA Zone 6b. The average last spring frost is April 7 and the first fall frost is October 21, giving you a growing season of approximately 197 days.

At an elevation of 1,120 feet, Pope County receives approximately 39.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Fennel (herb) during the growing season.

Pope County, IL (Zone 6b) Moderate season
197 days
Last Spring Frost April 7
197 growing days
First Fall Frost October 21

Pope County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (70 days to spare)
Start indoors: Feb 27 Transplant: Mar 27 🍅 Harvest: May 29 – Aug 7
Recommended (50%) ✓ Fits season (71 days to spare)
Start indoors: Mar 3 Transplant: Mar 31 🍅 Harvest: Jun 2 – Aug 11
Safe Start (90%) ✓ Fits season (71 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🍅 Harvest: Jun 16 – Aug 25

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
0.5″/week
Watering frequency 1-2 times/week
Season total 814 gal / 100 sq ft
Fennel (herb) needs ~1,369 GDD — county provides 3,595 GDD Excellent fit

Fennel (herb) Planting Timeline โ€” Pope County, IL

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 โ€“ Mar 17
Transplant Outdoors March 31 Mar 31 โ€“ Apr 14
Direct Sow March 24 Mar 24 โ€“ Apr 14
Fall Sowing August 12 Aug 12 โ€“ Aug 26
Harvest June 2 Jun 2 โ€“ Aug 11

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors Direct Sow
May โ€”
June Harvest
July Harvest
August Fall Sowing Harvest
September โ€”
October โ€”
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 6b

Growing Season

197 days

Growing Tips for Pope 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 Pope County, IL?

Pope County is in Zone 6b with an average last frost of April 7. Plan your Fennel (herb) planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Pope County, IL?

Pope County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 7 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Pope County gardeners in Zone 6b 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 Pope County, IL. Local conditions may vary. Last updated: April 2026.