When to plant Fennel in Sullivan County, MO
Sullivan County's spring Fennel window runs April 24 through May 15. time plantings around the expected last-frost window for best survival.
When to Plant Fennel in Sullivan County, MO
What to do in August
Here's what deserves your attention in Sullivan County, Missouri this month. Everything below is tailored to Zone 6a and timed around your local frost dates.
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Harvest fennel as they ripen
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
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.
Sullivan County, Missouri is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 17, giving you a growing season of approximately 183 days.
At an elevation of 1,019 feet, Sullivan County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Fennel to ensure they mature before fall.
Sullivan County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.8
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 Sullivan County
How your county's soil matches Fennel's growing requirements.
Soil pH
Your soil pH (5.5–6.8) is within Fennel's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Sullivan County is excellent for Fennel — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.1%). Annual compost additions will help Fennel.
How to Plant Fennel
Succession Planting Fennel
Sow every 6.9 weeks. Last sowing by Jul 19 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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | 2.6" | 3.1" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 4.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 3.9" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 3.2" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 2.6" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Sullivan 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 — Sullivan County, MO
Fennel Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 20 | Feb 20 – Mar 6 |
| Transplant Outdoors | May 1 | May 1 – May 15 |
| Direct Sow | April 24 | Apr 24 – May 15 |
| Harvest | July 3 | Jul 3 – Aug 14 |
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 6a
📆 Growing Season
183 days in Sullivan County
Growing Tips for Fennel in Sullivan County
Direct sow Fennel outdoors after April 17 in Sullivan 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 Sullivan County, MO?
Sullivan County is in Zone 6a with an average last frost of April 17. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sullivan County, MO?
Sullivan County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 17.
When should I plant Fennel in Sullivan County, MO?
In Sullivan County, MO, plant Fennel after the last frost (around April 17) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Sullivan County, MO for Fennel?
Sullivan County sits in USDA Zone 6a. Fennel grows reliably in zones 4a through 10b, so it's a good fit here.
Can Fennel grow in Sullivan County's climate?
Yes — Fennel grows well in Sullivan County's temperate climate. Sullivan County averages a 183-day frost-free season, with last frost around April 17 and first frost around October 17.
Your Sullivan County Garden Planner — Free
A 22-page printable planner built for Sullivan County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.