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When to Plant Potatoes in Wallowa County, OR

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

Wallowa County, Oregon is in USDA Zone 5a. The average last spring frost is May 11 and the first fall frost is September 22, giving you a growing season of approximately 134 days.

At an elevation of 1,240 feet, Wallowa County receives approximately 22.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Potatoes during the growing season.

Wallowa County, OR (Zone 5a) Short season
134 days
Last Spring Frost May 11
134 growing days
First Fall Frost September 22

Wallowa County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 6 Transplant: May 15 🍅 Harvest: Jul 24 – Oct 2
Recommended (50%) ✗ May not fit
Start indoors: Mar 16 Transplant: May 25 🍅 Harvest: Aug 3 – Oct 12
Safe Start (90%) ✗ May not fit
Start indoors: Apr 17 Transplant: Jun 26 🍅 Harvest: Sep 4 – Nov 13

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 Wallowa County

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

Soil pH

Your soil pH (5.3โ€“6.2) is within Potatoes's preferred range (5.0โ€“6.5).

Soil Texture

The silt loam soil in Wallowa County is excellent for Potatoes โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Potatoes.

Organic Matter

Organic matter is excellent (5.4%) โ€” Potatoes will thrive.

How to Plant Potatoes

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

Succession Planting Potatoes

2
successive plantings in your 134-day season

Sow every 8 weeks. Last sowing by May 25 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 706 gal / 100 sq ft

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 โ€” 2.9" 0" โ„๏ธ Dormant
Feb โ€” 2.3" 0" โ„๏ธ Dormant
Mar โ€” 2.1" 0" โ„๏ธ Dormant
Apr โ€” 1.5" 0" โ„๏ธ Dormant
May 4.3" 1.3" 3" ๐Ÿšฟ Regular watering
Jun 4.3" 1" 3.3" ๐Ÿšฟ Regular watering
Jul 4.3" 0.4" 3.9" ๐Ÿšฟ Regular watering
Aug 4.3" 0.4" 3.9" ๐Ÿšฟ Regular watering
Sep 4.3" 1" 3.3" ๐Ÿšฟ Regular watering
Oct โ€” 2.1" 0" โ„๏ธ Dormant
Nov โ€” 3.9" 0" โ„๏ธ Dormant
Dec โ€” 3.6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Wallowa County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,306 GDD — county provides 1,842 GDD Excellent fit

Potatoes Planting Timeline โ€” Wallowa County, OR

Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 โ€“ Mar 30
Transplant Outdoors May 25 May 25 โ€“ Jun 8
Direct Sow May 18 May 18 โ€“ Jun 8
Harvest August 3 Aug 3 โ€“ Oct 12

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 Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

70โ€“120 days

๐Ÿงช Soil pH

Needs 5โ€“6.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

134 days in Wallowa County

Growing Tips for Potatoes in Wallowa County

Direct sow Potatoes outdoors after May 11 in Wallowa 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.

Wallowa County receives only 23" of rain annually. Potatoes needs consistent moisture โ€” 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 Wallowa 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 Wallowa County, OR?

Wallowa County is in Zone 5a with an average last frost of May 11. Plan your Potatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Wallowa County, OR?

Wallowa County, Oregon is in USDA Hardiness Zone 5a. The average last spring frost is May 11 and first fall frost is September 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Wallowa County gardeners in Zone 5a 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 Wallowa County, OR. Local conditions may vary. Last updated: April 2026.