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When to Plant Sweet Potatoes in Tooele County, UT

Tooele County, Utah Zone 6b May

What to do in May

Your garden in Tooele County, Utah is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 1
Avg. first frost October 17
Soil temp (4") 52°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
  1. Move sweet potatoes into the garden

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Put sweet potatoes seeds straight in the ground

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

A few tasks this May that'll pay off in June
  • Starting indoors: sweet potatoes

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Sweet potatoes are a warm-season root crop that produces nutritious, sweet tubers in orange, white, and purple varieties. They need a long, hot growing season.

Tooele County, Utah is in USDA Zone 6b. The average last spring frost is May 1 and the first fall frost is October 17, giving you a growing season of approximately 169 days.

At an elevation of 4,309 feet, Tooele County receives approximately 12.6 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Sweet Potatoes during the growing season. With low rainfall, drip irrigation is essential for growing Sweet Potatoes successfully. Mulch heavily to conserve soil moisture.

Tooele County, UT (Zone 6b) Moderate season
169 days
Last Spring Frost May 1
169 growing days
First Fall Frost October 17

Tooele County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Feb 28 Transplant: May 9 🍅 Harvest: Aug 8 – Sep 26
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Mar 6 Transplant: May 15 🍅 Harvest: Aug 14 – Oct 2
Safe Start (90%) ✓ Fits season (10 days to spare)
Start indoors: Mar 23 Transplant: Jun 1 🍅 Harvest: Aug 31 – Oct 19

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 Tooele County

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

Soil pH

Your soil pH (6.3–7.8) is more alkaline than Sweet Potatoes prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

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

How to Plant Sweet Potatoes

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,240 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Sweet Potatoes

Sweet 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 Sweet Potatoes Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 1.2" 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" 3.3" 🚿 Regular watering
Aug 4.3" 1.4" 2.9" 🚿 Regular watering
Sep 4.3" 1" 3.3" 🚿 Regular watering
Oct 4.3" 1.2" 3.1" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

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

Sweet 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.

Sweet Potatoes needs ~1,759 GDD — county provides 2,830 GDD Excellent fit

Sweet Potatoes Planting Timeline — Tooele County, UT

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest August 14 Aug 14 – Oct 2

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
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

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

169 days in Tooele County

Growing Tips for Sweet Potatoes in Tooele County

Direct sow Sweet Potatoes outdoors after May 01 in Tooele County when soil has warmed and frost danger has passed.

Tooele County receives only 13" of rain annually. Sweet Potatoes needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant slips (rooted sprouts) after soil is thoroughly warm. Build raised mounds for better root development. Cure harvested roots at 80-85F for 10 days to develop sweetness.

Companion Planting

Good Companions

Avoid Planting Near

  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Potatoes in Tooele County, UT?

Tooele County is in Zone 6b with an average last frost of May 1. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tooele County, UT?

Tooele County, Utah is in USDA Hardiness Zone 6b. The average last spring frost is May 1 and first fall frost is October 17.

🌱

Your Tooele County Garden Planner — Free

A 24-page printable planner built for Tooele 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 Tooele County, UT. 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.