When to plant Fennel in Kendall County County,
In Kendall County County, plant Fennel in spring between April 27 and May 18, once soil temps hold above 50°F. Kendall County County's last frost averages April 20, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 90 days before the first frost on October 17.
When to Plant Fennel in Kendall County, IL
Your June gardening checklist
June is a pivotal month for Kendall County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Time to start fennel inside
Label every cell. You will absolutely forget which is which otherwise.
Before July arrives, get these ready
- First harvests: fennel
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.
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 during the growing season.
Kendall County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-6.8
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 Kendall County
How your county's soil matches Fennel's growing requirements.
Soil pH
Your soil pH (6.1–6.8) is within Fennel's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Kendall County is excellent for Fennel — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.9%) — Fennel will thrive.
How to Plant Fennel
Succession Planting Fennel
Sow every 6.9 weeks. Last sowing by Jul 19 to harvest before frost.
Fennel Water Budget
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 | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 3" | 0" | ❄️ Dormant |
| Apr | 2.6" | 3.9" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 5.3" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 4.1" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 3.4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 2.9" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Kendall 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 — Kendall County, IL
Fennel Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 23 | Feb 23 – Mar 9 |
| Transplant Outdoors | May 4 | May 4 – May 18 |
| Direct Sow | April 27 | Apr 27 – May 18 |
| Harvest | July 6 | Jul 6 – Aug 17 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| 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 5b
📆 Growing Season
180 days in Kendall County
Growing Tips for Fennel in Kendall County
Direct sow Fennel outdoors after April 20 in Kendall 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 Kendall County, IL?
Kendall County is in Zone 5b with an average last frost of April 20. Plan your Fennel 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 in Kendall County, ?
In Kendall County, , plant Fennel 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, for Fennel?
Kendall County sits in USDA Zone 5b. Fennel grows reliably in zones 4a through 10b, so it's a good fit here.
Can Fennel grow in Kendall County's climate?
Yes — Fennel 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.