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When to Plant Potatoes in Shoshone County, ID

Shoshone County, Idaho Zone 6b May

May in the garden — Shoshone County, Idaho

A quick May briefing for Shoshone County, Idaho gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 10
Avg. first frost September 26
Soil temp (4") 41°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Get potatoes in the ground

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Plant potatoes from seed, right in the garden

    Your soil is 41°F — warm enough for these to germinate without babying.

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

Shoshone County, Idaho is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is September 26, giving you a growing season of approximately 139 days.

At an elevation of 6,353 feet, Shoshone County receives approximately 14.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Potatoes to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Potatoes successfully. Mulch heavily to conserve soil moisture.

Shoshone County, ID (Zone 6b) Short season
139 days
Last Spring Frost May 10
139 growing days
First Fall Frost September 26

Shoshone County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 8 Transplant: May 17 🍅 Harvest: Jul 26 – Oct 4
Recommended (50%) ✗ May not fit
Start indoors: Mar 15 Transplant: May 24 🍅 Harvest: Aug 2 – Oct 11
Safe Start (90%) ✗ May not fit
Start indoors: Apr 9 Transplant: Jun 18 🍅 Harvest: Aug 27 – Nov 5

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 Shoshone County

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

Soil pH

Your soil pH (6.6–7.7) is more alkaline than Potatoes prefers (5.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Potatoes.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Potatoes.

How to Plant Potatoes

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Potatoes

2
successive plantings in your 139-day season

Sow every 8 weeks. Last sowing by May 29 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,297 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Potatoes

Potatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Potatoes Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 4.3" 1.9" 2.4" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 1.2" 3.1" 🚿 Regular watering
Aug 4.3" 1.5" 2.8" 🚿 Regular watering
Sep 4.3" 1.3" 3" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

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

Potatoes 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.

Potatoes needs ~1,235 GDD — county provides 1,807 GDD Excellent fit

Potatoes Planting Timeline — Shoshone County, ID

Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 17 May 17 – Jun 7
Harvest August 2 Aug 2 – Oct 11

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors 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

1"/week · 2-3 times/week

📅 Days to Maturity

70–120 days

🧪 Soil pH

Needs 5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

139 days in Shoshone County

Growing Tips for Potatoes in Shoshone County

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

Common pests for Potatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

Shoshone County receives only 14" of rain annually. Potatoes needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

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.

Recommended Potatoes Varieties for Shoshone County

Early-maturing potatoes for your season

Yukon Gold (65d) Red Norland (70d) Irish Cobbler (70d)

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 Shoshone County, ID?

Shoshone County is in Zone 6b with an average last frost of May 10. Plan your Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Shoshone County, ID?

Shoshone County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 10 and first fall frost is September 26.

🌱

Your Shoshone County Garden Planner — Free

A 24-page printable planner built for Shoshone County (Zone 6b). 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 Shoshone County, ID. 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.