When to Plant Radish in Clark County, SD
Your May planting checklist for Clark County, South Dakota
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Clark County, South Dakota.
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Harvest radish as they ripen
If you can't use it all right away, check the food-preservation section of your planner.
Get ahead of June
- First harvests: radish
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.
Clark County, South Dakota is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 5, giving you a growing season of approximately 155 days.
At an elevation of 799 feet, Clark County receives approximately 28.2 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Radish to ensure they mature before fall.
Clark County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.3
Drainage
Well Drained
Plant Planting Risk Windows
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 Clark County
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (6.3–7.3) overlaps with Radish's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Clark County is excellent for Radish — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Radish.
Organic Matter
Organic matter is moderate (4.0%). Annual compost additions will help Radish.
How to Plant Radish
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Radish
Sow every 2.4 weeks. Last sowing by Aug 31 to harvest before frost.
For a dedicated fall crop, sow by Jul 13.
Plant Water Budget
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 | — | 0.6" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 2.6" | 0" | ❄️ Dormant |
| May | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Nov | — | 0.9" | 0" | ❄️ Dormant |
| Dec | — | 0.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Clark 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 Planting Timeline — Clark 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 13 | Jul 13 – Jul 27 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow Harvest |
| June | Harvest |
| July | Fall Sowing |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
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 4b
📆 Growing Season
155 days in Clark County
Growing Tips for Radish in Clark County
Direct sow Radish outdoors after May 03 in Clark County when soil has warmed and frost danger has passed.
Your generous 155.0-day season in Clark 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
Check more plant combinations with our Companion Planting Checker →
Radish in Other Locations
Frequently Asked Questions
When should I plant Radish in Clark County, SD?
Clark County is in Zone 4b with an average last frost of May 3. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clark County, SD?
Clark County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 5.
Your Clark County Garden Planner — Free
A 24-page printable planner built for Clark County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.