Blog

When to Plant Arugula in Mille Lacs County, MN

Arugula is a fast-growing cool-season green with a peppery, nutty flavor. It is excellent in salads and can be harvested as baby greens or mature leaves.

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 Arugula 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 (58 days to spare)
Start indoors: Mar 14 Transplant: Apr 25 🍅 Harvest: May 30 – Aug 1
Recommended (50%) ✓ Fits season (60 days to spare)
Start indoors: Mar 20 Transplant: May 1 🍅 Harvest: Jun 5 – Aug 7
Safe Start (90%) ✓ Fits season (56 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Jun 22 – Aug 24

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
Arugula needs ~400 GDD — county provides 1,580 GDD Excellent fit

Arugula Planting Timeline โ€” Mille Lacs County, MN

Arugula Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 โ€“ Apr 3
Transplant Outdoors May 1 May 1 โ€“ May 15
Direct Sow April 24 Apr 24 โ€“ May 15
Fall Sowing July 14 Jul 14 โ€“ Jul 28
Harvest June 5 Jun 5 โ€“ Aug 7

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

30โ€“50 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4a

Growing Season

158 days

Growing Tips for Mille Lacs County

Sow seeds directly every 2-3 weeks for continuous harvest. Provide afternoon shade in warm weather to prevent bolting. Harvest outer leaves first to extend production.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

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

Mille Lacs County is in Zone 4a with an average last frost of May 1. Plan your Arugula 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.