Blog

When to Plant Potatoes in Fall River County, SD

Potatoes are a versatile staple crop that produces tubers underground. They come in hundreds of varieties with varying colors, textures, and maturity dates.

Fall River County, South Dakota is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is October 1, giving you a growing season of approximately 140 days.

At an elevation of 1,056 feet, Fall River County receives approximately 25.4 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Potatoes to ensure they mature before fall.

Fall River County, SD (Zone 4b) Short season
140 days
Last Spring Frost May 14
140 growing days
First Fall Frost October 1

Fall River County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 9 Transplant: Jun 1 🍅 Harvest: Aug 10 – Oct 19
Recommended (50%) ✗ May not fit
Start indoors: Mar 12 Transplant: Jun 4 🍅 Harvest: Aug 13 – Oct 22
Safe Start (90%) ✗ May not fit
Start indoors: Mar 24 Transplant: Jun 16 🍅 Harvest: Aug 25 – Nov 3

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
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 356 gal / 100 sq ft
Drought risk

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

Potatoes needs ~1,235 GDD — county provides 1,820 GDD Excellent fit

Potatoes Planting Timeline โ€” Fall River County, SD

Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 โ€“ Mar 26
Transplant Outdoors June 4 Jun 4 โ€“ Jun 18
Direct Sow May 28 May 28 โ€“ Jun 18
Harvest August 13 Aug 13 โ€“ Oct 22

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April โ€”
May Direct Sow
June Transplant Outdoors Direct Sow
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

70โ€“120 days

Soil pH

5 โ€“ 6.5

USDA Zone

Zone 4b

Growing Season

140 days

Growing Tips for Fall River County

Plant seed potatoes (not grocery store potatoes) 4 inches deep in spring. Hill soil around stems as plants grow to prevent greening. Stop watering when plants die back.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Cucumber
  • Squash Summer

Level Up Your Garden

Frequently Asked Questions

When should I plant Potatoes in Fall River County, SD?

Fall River County is in Zone 4b with an average last frost of May 14. Plan your Potatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Fall River County, SD?

Fall River County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is October 1.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Fall River County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Fall River County, SD. Local conditions may vary. Last updated: April 2026.