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When to plant Potatoes in Franklin County, ID

Franklin County's 137-day season only supports one Potatoes planting per year. Sow between May 26 and June 16 for the best chance at full maturity before October 3.

When to Plant Potatoes in Franklin County, ID

Potatoes

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

Franklin County, Idaho is in USDA Zone 6a. The average last spring frost is May 19 and the first fall frost is October 3, giving you a growing season of approximately 137 days.

At an elevation of 7,665 feet, Franklin County receives approximately 18.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Potatoes during the growing season. With low rainfall, drip irrigation is essential for growing Potatoes successfully. Mulch heavily to conserve soil moisture.

Franklin County, ID (Zone 6a) Short season
137 days
Last Spring Frost May 19
137 growing days
First Fall Frost October 3

Franklin County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

How Much Potatoes to Grow

3-5 lbs
Average yield per plant
5
Plants per person
10 sq ft
Space per person

For a family of 4, plant approximately 20 potatoes plants in about 40 sq ft. In Franklin County's 137-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Potatoes Planting Timeline — Franklin County, ID

Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 24 Mar 24 – Apr 7
Transplant Outdoors June 2 Jun 2 – Jun 16
Direct Sow May 26 May 26 – Jun 16
Harvest August 11 Aug 11 – Oct 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

70–120 days

🧪 Soil pH

Needs 5–6.5 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

137 days in Franklin County

Growing Tips for Franklin 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Potatoes in Franklin County, ID?

Franklin County is in Zone 6a with an average last frost of May 19. Plan your Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Franklin County, ID?

Franklin County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is May 19 and first fall frost is October 3.

When should I plant Potatoes in Franklin County, ID?

In Franklin County, ID, plant Potatoes after the last frost (around May 19) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Franklin County, ID for Potatoes?

Franklin County sits in USDA Zone 6a. Potatoes grows reliably in zones 3a through 10b, so it's a good fit here.

Can Potatoes grow in Franklin County's climate?

Yes — Potatoes grows well in Franklin County's temperate climate. Franklin County averages a 137-day frost-free season, with last frost around May 19 and first frost around October 3.

🌱

Your Franklin County Garden Planner — Free

A 22-page printable planner built for Franklin County (Zone 6a). 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 Franklin County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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