When to Plant Fennel (herb) in Henry 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.
Henry County, Illinois is in USDA Zone 5a. The average last spring frost is April 16 and the first fall frost is October 16, giving you a growing season of approximately 183 days.
At an elevation of 593 feet, Henry County receives approximately 31.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Fennel (herb) during the growing season.
Henry County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-7.2
Drainage
Well Drained
Plant Planting Risk Windows
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
Fennel (herb) Planting Timeline — Henry County, IL
Fennel (herb) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 12 | Mar 12 – Mar 26 |
| Transplant Outdoors | April 9 | Apr 9 – Apr 23 |
| Direct Sow | April 2 | Apr 2 – Apr 23 |
| Fall Sowing | August 7 | Aug 7 – Aug 21 |
| Harvest | June 11 | Jun 11 – Aug 20 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
5.5 – 7
USDA Zone
Zone 5a
Growing Season
183 days
Growing Tips for Henry 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
Level Up Your Garden
Fennel (herb) in Other Locations
Frequently Asked Questions
When should I plant Fennel (herb) in Henry County, IL?
Henry County is in Zone 5a with an average last frost of April 16. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Henry County, IL?
Henry County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 16 and first fall frost is October 16.
Plan Your Garden with Confidence
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