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When to Plant Radish in Blue Earth County, MN

Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

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 Radish 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 (107 days to spare)
Transplant: Apr 24 🍅 Harvest: May 22 – Jun 12
Recommended (50%) ✓ Fits season (109 days to spare)
Transplant: Apr 29 🍅 Harvest: May 27 – Jun 17
Safe Start (90%) ✓ Fits season (106 days to spare)
Transplant: May 14 🍅 Harvest: Jun 11 – Jul 2

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

Radish needs ~328 GDD — county provides 1,817 GDD Excellent fit

Radish Planting Timeline โ€” Blue Earth County, MN

Radish Planting Calendar

Activity When Date Range
Direct Sow April 22 Apr 22 โ€“ May 13
Fall Sowing July 12 Jul 12 โ€“ Jul 26
Harvest May 20 May 20 โ€“ Jun 10

Plant 0.5" deep ยท 2" apart ยท Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

22โ€“35 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4b

Growing Season

158 days

Growing Tips for Blue Earth County

Direct sow every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Level Up Your Garden

Frequently Asked Questions

When should I plant Radish in Blue Earth County, MN?

Blue Earth County is in Zone 4b with an average last frost of April 29. Plan your Radish 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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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 Blue Earth County, MN. Local conditions may vary. Last updated: April 2026.