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When to Plant Radish in Gregory County, SD

Gregory County, South Dakota Zone 5a May

Your May game plan for Gregory County, South Dakota

May is a pivotal month for Gregory County, South Dakota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 10
Avg. first frost October 6
Soil temp (4") 57°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Bring in the radish

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

June prep starts now
  • First harvests: radish

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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.

Gregory County, South Dakota is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is October 6, giving you a growing season of approximately 149 days.

At an elevation of 668 feet, Gregory County receives approximately 34.5 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Radish to ensure they mature before fall.

Gregory County, SD (Zone 5a) Short season
149 days
Last Spring Frost May 10
149 growing days
First Fall Frost October 6
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Gregory County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (106 days to spare)
Transplant: Apr 30 🍅 Harvest: May 28 – Jun 18
Recommended (50%) ✓ Fits season (100 days to spare)
Transplant: May 10 🍅 Harvest: Jun 7 – Jun 28
Safe Start (90%) ✓ Fits season (105 days to spare)
Transplant: May 19 🍅 Harvest: Jun 16 – Jul 7

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.

Soil Compatibility in Gregory County

How your county's soil matches Radish's growing requirements.

Soil pH

Your soil pH (6.4–7.4) overlaps with Radish's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Gregory County is excellent for Radish — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Radish.

How to Plant Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Radish

8
successive plantings in your 149-day season

Sow every 2.4 weeks. Last sowing by Sep 01 to harvest before frost.

For a dedicated fall crop, sow by Jul 28.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Radish

Radish needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Radish Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 2.2" 5.8" 0" ✅ Rainfall sufficient
Jun 2.2" 5" 0" ✅ Rainfall sufficient
Jul 2.2" 4.8" 0" ✅ Rainfall sufficient
Aug 2.2" 4.1" 0" ✅ Rainfall sufficient
Sep 2.2" 3.3" 0" ✅ Rainfall sufficient
Oct 2.2" 1.9" 0.3" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Gregory County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Radish Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Radish needs ~328 GDD — county provides 1,713 GDD Excellent fit

Radish Planting Timeline — Gregory County, SD

Radish Planting Calendar

Activity When Date Range
Direct Sow April 26 Apr 26 – May 17
Harvest May 24 May 24 – Jun 14
Fall Sowing July 28 Jul 28 – Aug 11

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May Direct Sow Harvest
June Harvest
July Fall Sowing
August Fall Sowing
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

149 days in Gregory County

Growing Tips for Radish in Gregory County

Direct sow Radish outdoors after May 10 in Gregory County when soil has warmed and frost danger has passed.

Your generous 149.0-day season in Gregory County allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.

Common pests for Radish in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in Gregory County, SD?

Gregory County is in Zone 5a with an average last frost of May 10. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gregory County, SD?

Gregory County, South Dakota is in USDA Hardiness Zone 5a. The average last spring frost is May 10 and first fall frost is October 6.

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Your Gregory County Garden Planner — Free

A 24-page printable planner built for Gregory County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Gregory County, SD. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.