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When to Plant Radish in Mellette County, SD

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.

Mellette County, South Dakota is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is October 4, giving you a growing season of approximately 146 days.

At an elevation of 1,123 feet, Mellette County receives approximately 33.3 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Radish to ensure they mature before fall.

Mellette County, SD (Zone 4b) Short season
146 days
Last Spring Frost May 11
146 growing days
First Fall Frost October 4

Mellette County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (99 days to spare)
Transplant: May 3 🍅 Harvest: May 31 – Jun 21
Recommended (50%) ✓ Fits season (97 days to spare)
Transplant: May 11 🍅 Harvest: Jun 8 – Jun 29
Safe Start (90%) ✓ Fits season (98 days to spare)
Transplant: May 21 🍅 Harvest: Jun 18 – Jul 9

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
0.1″/week
Watering frequency Only during dry spells
Season total 66 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Radish needs ~328 GDD — county provides 1,679 GDD Excellent fit

Radish Planting Timeline โ€” Mellette County, SD

Radish Planting Calendar

Activity When Date Range
Direct Sow May 4 May 4 โ€“ May 25
Fall Sowing July 12 Jul 12 โ€“ Jul 26
Harvest June 1 Jun 1 โ€“ Jun 22

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 4b

Growing Season

146 days

Growing Tips for Mellette 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 Mellette County, SD?

Mellette County is in Zone 4b with an average last frost of May 11. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Mellette County, SD?

Mellette County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is October 4.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Mellette 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 Mellette County, SD. Local conditions may vary. Last updated: April 2026.