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When to Plant Potatoes in Sweetwater County, WY

Sweetwater County, Wyoming Zone 5a May

May in Sweetwater County, Wyoming — your action list

Each item below is timed to Sweetwater County, Wyoming's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 29
Avg. first frost September 20
Soil temp (4") 31°F
Watering High
Pest pressure Low
Daylight 14.3 hrs
To set up a strong June, finish these tasks
  • Transplants going out: potatoes
  • Direct-sowing: potatoes

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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.

Sweetwater County, Wyoming is in USDA Zone 5a. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.

At an elevation of 7,922 feet, Sweetwater County receives approximately 12.9 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.

Sweetwater County, WY (Zone 5a) Short season
114 days
Last Spring Frost May 29
114 growing days
First Fall Frost September 20

Sweetwater County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 24 Transplant: Jun 2 🍅 Harvest: Aug 11 – Oct 20
Recommended (50%) ✗ May not fit
Start indoors: Apr 3 Transplant: Jun 12 🍅 Harvest: Aug 21 – Oct 30
Safe Start (90%) ✗ May not fit
Start indoors: Apr 21 Transplant: Jun 30 🍅 Harvest: Sep 8 – Nov 17

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 Sweetwater County

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

Soil pH

Your soil pH (6.2–7.7) is more alkaline than Potatoes prefers (5.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Sweetwater 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 (2.4%). Annual compost additions will help Potatoes.

How to Plant Potatoes

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

How Much Potatoes to Grow

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

For a family of 4, plant approximately 20 potatoes plants in about 50 sq ft. In Sweetwater County's 114-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,004 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 0.8" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 4.3" 1.5" 2.8" 🚿 Regular watering
Jun 4.3" 1" 3.3" 🚿 Regular watering
Jul 4.3" 1.1" 3.2" 🚿 Regular watering
Aug 4.3" 1.3" 3" 🚿 Regular watering
Sep 4.3" 1" 3.3" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Sweetwater 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 1,482 GDD Good fit

Potatoes Planting Timeline — Sweetwater County, WY

Potatoes Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors June 12 Jun 12 – Jun 26
Direct Sow June 5 Jun 5 – Jun 26
Harvest August 21 Aug 21 – Oct 30

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May
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 5a

📆 Growing Season

114 days in Sweetwater County

Growing Tips for Potatoes in Sweetwater County

Direct sow Potatoes outdoors after May 29 in Sweetwater County when soil has warmed and frost danger has passed.

Your 114.0-day growing season in Sweetwater County is tight for Potatoes (70.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Sweetwater County receives only 13" 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 Sweetwater 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 Sweetwater County, WY?

Sweetwater County is in Zone 5a with an average last frost of May 29. Plan your Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sweetwater County, WY?

Sweetwater County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 29 and first fall frost is September 20.

🌱

Your Sweetwater County Garden Planner — Free

A 24-page printable planner built for Sweetwater County (Zone 5a). 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 Sweetwater County, WY. 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.