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When to Plant Arugula in Blue Earth 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.

Blue Earth County, Minnesota is in USDA Zone 4b. The average last spring frost is April 29 and the first fall frost is October 4, giving you a growing season of approximately 158 days.

At an elevation of 646 feet, Blue Earth County receives approximately 40.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Arugula to ensure they mature before fall.

Blue Earth County, MN (Zone 4b) Moderate season
158 days
Last Spring Frost April 29
158 growing days
First Fall Frost October 4

Blue Earth County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Mar 13 Transplant: Apr 24 🍅 Harvest: May 29 – Jul 31
Recommended (50%) ✓ Fits season (60 days to spare)
Start indoors: Mar 18 Transplant: Apr 29 🍅 Harvest: Jun 3 – Aug 5
Safe Start (90%) ✓ Fits season (57 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jun 18 – Aug 20

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Arugula needs ~460 GDD — county provides 1,817 GDD Excellent fit

Arugula Planting Timeline โ€” Blue Earth County, MN

Arugula Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 โ€“ Apr 1
Transplant Outdoors April 29 Apr 29 โ€“ May 13
Direct Sow April 22 Apr 22 โ€“ May 13
Fall Sowing July 12 Jul 12 โ€“ Jul 26
Harvest June 3 Jun 3 โ€“ Aug 5

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 Transplant Outdoors 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 4b

Growing Season

158 days

Growing Tips for Blue Earth 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 Blue Earth County, MN?

Blue Earth County is in Zone 4b with an average last frost of April 29. Plan your Arugula planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Blue Earth County, MN?

Blue Earth County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 29 and first fall frost is October 4.

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Plan Your Garden with Confidence

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

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