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When to Plant Radish in Douglas 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.

Douglas County, Wisconsin is in USDA Zone 3b. The average last spring frost is May 16 and the first fall frost is September 28, giving you a growing season of approximately 135 days.

At an elevation of 1,147 feet, Douglas County receives approximately 31.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79ยฐF, so choose short-season varieties of Radish to ensure they mature before fall.

Douglas County, WI (Zone 3b) Short season
135 days
Last Spring Frost May 16
135 growing days
First Fall Frost September 28

Douglas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (84 days to spare)
Transplant: May 10 🍅 Harvest: Jun 7 – Jun 28
Recommended (50%) ✓ Fits season (86 days to spare)
Transplant: May 16 🍅 Harvest: Jun 13 – Jul 4
Safe Start (90%) ✓ Fits season (86 days to spare)
Transplant: May 30 🍅 Harvest: Jun 27 – Jul 18

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 28 gal / 100 sq ft
Radish needs ~264 GDD — county provides 1,248 GDD Excellent fit

Radish Planting Timeline โ€” Douglas County, WI

Radish Planting Calendar

Activity When Date Range
Direct Sow May 9 May 9 โ€“ May 30
Fall Sowing July 6 Jul 6 โ€“ Jul 20
Harvest June 6 Jun 6 โ€“ Jun 27

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Direct Sow
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 3b

Growing Season

135 days

Growing Tips for Douglas 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 Douglas County, WI?

Douglas County is in Zone 3b with an average last frost of May 16. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Douglas County, WI?

Douglas County, Wisconsin is in USDA Hardiness Zone 3b. The average last spring frost is May 16 and first fall frost is September 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Douglas County gardeners in Zone 3b 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 Douglas County, WI. Local conditions may vary. Last updated: April 2026.