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When to Plant Radish in Milwaukee County, WI

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.

Milwaukee County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 27 and the first fall frost is October 11, giving you a growing season of approximately 167 days.

At an elevation of 1,100 feet, Milwaukee County receives approximately 38.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Radish during the growing season.

Milwaukee County, WI (Zone 5b) Moderate season
167 days
Last Spring Frost April 27
167 growing days
First Fall Frost October 11

Milwaukee County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (117 days to spare)
Transplant: Apr 22 🍅 Harvest: May 20 – Jun 10
Recommended (50%) ✓ Fits season (118 days to spare)
Transplant: Apr 27 🍅 Harvest: May 25 – Jun 15
Safe Start (90%) ✓ Fits season (116 days to spare)
Transplant: May 13 🍅 Harvest: Jun 10 – Jul 1

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
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 55 gal / 100 sq ft
Radish needs ~413 GDD — county provides 2,421 GDD Excellent fit

Radish Planting Timeline โ€” Milwaukee County, WI

Radish Planting Calendar

Activity When Date Range
Direct Sow April 13 Apr 13 โ€“ May 4
Fall Sowing August 2 Aug 2 โ€“ Aug 16
Harvest May 11 May 11 โ€“ Jun 1

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 โ€”
August Fall Sowing
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 5b

Growing Season

167 days

Growing Tips for Milwaukee 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 Milwaukee County, WI?

Milwaukee County is in Zone 5b with an average last frost of April 27. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Milwaukee County, WI?

Milwaukee County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 27 and first fall frost is October 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Milwaukee County gardeners in Zone 5b 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 Milwaukee County, WI. Local conditions may vary. Last updated: April 2026.