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When to Plant Sweet Potatoes in Bear Lake County, ID

Bear Lake County, Idaho Zone 5a May

Your May planting checklist for Bear Lake County, Idaho

May is a pivotal month for Bear Lake County, Idaho gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 24
Avg. first frost September 24
Soil temp (4") 42°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Put sweet potatoes seeds straight in the ground

    Your soil is 42°F — warm enough for these to germinate without babying.

Coming up in June — start thinking about
  • Transplants going out: 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.

Bear Lake County, Idaho is in USDA Zone 5a. The average last spring frost is May 24 and the first fall frost is September 24, giving you a growing season of approximately 123 days.

At an elevation of 5,220 feet, Bear Lake County receives approximately 18.6 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Sweet Potatoes to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Sweet Potatoes successfully. Mulch heavily to conserve soil moisture.

Bear Lake County, ID (Zone 5a) Short season
123 days
Last Spring Frost May 24
123 growing days
First Fall Frost September 24

Bear Lake County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 11 Transplant: May 20 🍅 Harvest: Aug 19 – Oct 7
Recommended (50%) ✗ May not fit
Start indoors: Mar 29 Transplant: Jun 7 🍅 Harvest: Sep 6 – Oct 25
Safe Start (90%) ✗ May not fit
Start indoors: Apr 27 Transplant: Jul 6 🍅 Harvest: Oct 5 – Nov 23

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 Bear Lake County

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

Soil pH

Your soil pH (6.7–8.2) 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 Bear Lake County is excellent for Sweet Potatoes — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). 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
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 479 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.1" 3.2" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Bear Lake 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 ~1,286 GDD — county provides 1,506 GDD Good fit

Sweet Potatoes Planting Timeline — Bear Lake County, ID

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors June 7 Jun 7 – Jun 21
Direct Sow May 31 May 31 – Jun 21
Harvest September 6 Sep 6 – Oct 25

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
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

123 days in Bear Lake County

Growing Tips for Sweet Potatoes in Bear Lake County

Direct sow Sweet Potatoes outdoors after May 24 in Bear Lake County when soil has warmed and frost danger has passed.

Your 123.0-day growing season in Bear Lake County is tight for Sweet Potatoes (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Bear Lake County receives only 19" 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 Bear Lake County, ID?

Bear Lake County is in Zone 5a with an average last frost of May 24. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bear Lake County, ID?

Bear Lake County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 24 and first fall frost is September 24.

🌱

Your Bear Lake County Garden Planner — Free

A 24-page printable planner built for Bear Lake 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 Bear Lake 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.