Blog

When to Plant Fennel in Mille Lacs County, MN

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.

Mille Lacs County, Minnesota is in USDA Zone 4a. The average last spring frost is May 1 and the first fall frost is October 6, giving you a growing season of approximately 158 days.

At an elevation of 874 feet, Mille Lacs County receives approximately 31.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Fennel to ensure they mature before fall.

Mille Lacs County, MN (Zone 4a) Moderate season
158 days
Last Spring Frost May 1
158 growing days
First Fall Frost October 6

Mille Lacs County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Feb 21 Transplant: May 16 🍅 Harvest: Jul 18 – Aug 29
Recommended (50%) ✓ Fits season (32 days to spare)
Start indoors: Feb 27 Transplant: May 22 🍅 Harvest: Jul 24 – Sep 4
Safe Start (90%) ✓ Fits season (28 days to spare)
Start indoors: Mar 16 Transplant: Jun 8 🍅 Harvest: Aug 10 – Sep 21

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

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 236 gal / 100 sq ft
Fennel needs ~750 GDD — county provides 1,580 GDD Excellent fit

Fennel Planting Timeline โ€” Mille Lacs County, MN

Fennel Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 โ€“ Mar 13
Transplant Outdoors May 22 May 22 โ€“ Jun 5
Direct Sow May 15 May 15 โ€“ Jun 5
Harvest July 24 Jul 24 โ€“ Sep 4

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors
April โ€”
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 4a

Growing Season

158 days

Growing Tips for Mille Lacs County

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

  • Tomatoes
  • Peppers
  • Beans

Level Up Your Garden

Frequently Asked Questions

When should I plant Fennel in Mille Lacs County, MN?

Mille Lacs County is in Zone 4a with an average last frost of May 1. Plan your Fennel planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Mille Lacs County, MN?

Mille Lacs County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 1 and first fall frost is October 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Mille Lacs County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Mille Lacs County, MN. Local conditions may vary. Last updated: April 2026.