When to Plant Fennel in Walworth County, SD
May to-do list for Walworth County, South Dakota
May is a pivotal month for Walworth County, South Dakota gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Move fennel into the garden
Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.
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Seed fennel outdoors
Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.
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.
Walworth County, South Dakota is in USDA Zone 4b. The average last spring frost is May 10 and the first fall frost is October 1, giving you a growing season of approximately 144 days.
At an elevation of 1,070 feet, Walworth County receives approximately 30.2 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Fennel to ensure they mature before fall.
Walworth County Soil Profile
Soil Type
Loam
Soil pH
6.5-7.8
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.
Soil Compatibility in Walworth County
How your county's soil matches Fennel's growing requirements.
Soil pH
Your soil pH (6.5–7.8) is more alkaline than Fennel prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Walworth County is excellent for Fennel — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.5%). Annual compost additions will help Fennel.
How to Plant Fennel
Succession Planting Fennel
Sow every 6.9 weeks. Last sowing by Jul 03 to harvest before frost.
Plant 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 | — | 2.1" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | — | 2.9" | 0" | ❄️ Dormant |
| May | 2.6" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 1.9" | 0.7" | 💧 Light watering |
| Jul | 2.6" | 2.7" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 2.8" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 2.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 2.8" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Walworth 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 — Walworth County, SD
Fennel Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 8 | Mar 8 – Mar 22 |
| Transplant Outdoors | May 31 | May 31 – Jun 14 |
| Direct Sow | May 24 | May 24 – Jun 14 |
| Harvest | August 2 | Aug 2 – Sep 13 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| 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: too_alkaline
🗺️ USDA Zone
Zone 4b
📆 Growing Season
144 days in Walworth County
Growing Tips for Fennel in Walworth County
Direct sow Fennel outdoors after May 10 in Walworth 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 Walworth County, SD?
Walworth County is in Zone 4b with an average last frost of May 10. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.
What planting zone is Walworth County, SD?
Walworth County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 10 and first fall frost is October 1.
Your Walworth County Garden Planner — Free
A 24-page printable planner built for Walworth County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.