When to plant Fennel in Hamilton County, IL
Plant Fennel in Hamilton County after April 9; the prime window is April 16–May 7.
When to Plant Fennel in Hamilton County, IL
Hamilton County, Illinois gardeners: here's your August plan
We've pulled the most time-sensitive tasks for Hamilton County, Illinois this August and put them front and centre. Tackle them in order.
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Harvest fennel as they ripen
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
Florence fennel is grown for its swollen bulb-like stem base, which has a mild anise flavor. It is crisp raw in salads and sweet when roasted or braised.
Hamilton County, Illinois is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 23, giving you a growing season of approximately 197 days.
At an elevation of 524 feet, Hamilton County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Fennel during the growing season.
Hamilton County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.7
Drainage
Well Drained
Fennel 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.
Soil Compatibility in Hamilton County
How your county's soil matches Fennel's growing requirements.
Soil pH
Your soil pH (5.8–6.7) is within Fennel's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Hamilton County is excellent for Fennel — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.0%) — Fennel will thrive.
How to Plant Fennel
Succession Planting Fennel
Sow every 6.9 weeks. Last sowing by Jul 25 to harvest before frost.
Fennel Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Fennel
Fennel needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.
| Month | Fennel Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | — | 2.9" | 0" | ❄️ Dormant |
| Apr | 2.6" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 4.2" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 3.7" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.1" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 3.2" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Hamilton County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Fennel 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 Planting Timeline — Hamilton County, IL
Fennel Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 12 | Feb 12 – Feb 26 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 16 | Apr 16 – May 7 |
| Harvest | June 25 | Jun 25 – Aug 6 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.6"/week · Natural rainfall sufficient
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 5.5–7 · Your soil: ideal
🗺️ USDA Zone
Zone 6b
📆 Growing Season
197 days in Hamilton County
Growing Tips for Fennel in Hamilton County
Direct sow Fennel outdoors after April 09 in Hamilton County when soil has warmed and frost danger has passed.
Common pests for Fennel 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 late summer for fall harvest to reduce bolting. Hill soil around bulbs as they enlarge. Harvest when bulbs are tennis-ball sized before they elongate.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Fennel in Other Locations
Frequently Asked Questions
When should I plant Fennel in Hamilton County, IL?
Hamilton County is in Zone 6b with an average last frost of April 9. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hamilton County, IL?
Hamilton County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 23.
When should I plant Fennel in Hamilton County, IL?
In Hamilton County, IL, plant Fennel after the last frost (around April 9) and before the first frost (around October 23). Best results when soil holds above 50°F.
What growing zone is Hamilton County, IL for Fennel?
Hamilton County sits in USDA Zone 6b. Fennel grows reliably in zones 4a through 10b, so it's a good fit here.
Can Fennel grow in Hamilton County's climate?
Yes — Fennel grows well in Hamilton County's temperate climate. Hamilton County averages a 197-day frost-free season, with last frost around April 9 and first frost around October 23.
Your Hamilton County Garden Planner — Free
A 22-page printable planner built for Hamilton 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.