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When to Plant Watermelon in Bear Lake County, ID

Bear Lake County, Idaho Zone 5a May

May in Bear Lake County, Idaho — your action list

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

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. Plant watermelon from seed, right in the garden

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

Looking ahead to June
  • Transplants going out: watermelon
  • Starting indoors: watermelon

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Watermelon is a sprawling vine crop that produces sweet, juicy fruits in hot weather. Varieties range from personal-sized icebox types to 50-pound giants.

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 Watermelon to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Watermelon 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: Apr 1 Transplant: May 20 🍅 Harvest: Jul 29 – Sep 16
Recommended (50%) ✗ May not fit
Start indoors: Apr 19 Transplant: Jun 7 🍅 Harvest: Aug 16 – Oct 4
Safe Start (90%) ✗ May not fit
Start indoors: May 18 Transplant: Jul 6 🍅 Harvest: Sep 14 – Nov 2

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 Watermelon's growing requirements.

Soil pH

Your soil pH (6.7–8.2) overlaps with Watermelon's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Bear Lake County is excellent for Watermelon — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Watermelon.

How to Plant Watermelon

1"
Planting Depth
30"
Between Plants
42"
Between Rows

How Much Watermelon to Grow

15-20 lbs
Average yield per plant
1
Plants per person
8.8 sq ft
Space per person

For a family of 4, plant approximately 4 watermelon plants in about 35 sq ft. In Bear Lake County's 123-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,136 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Watermelon

Watermelon needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Watermelon 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 6.5" 2.5" 4" 🚿 Regular watering
Jun 6.5" 1.1" 5.4" 🚿 Regular watering
Jul 6.5" 1.6" 4.9" 🚿 Regular watering
Aug 6.5" 2" 4.5" 🚿 Regular watering
Sep 6.5" 1.5" 5" 🚿 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.

Watermelon 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.

Watermelon needs ~1,041 GDD — county provides 1,506 GDD Excellent fit

Watermelon Planting Timeline — Bear Lake County, ID

Watermelon Planting Calendar

Activity When Date Range
Start Indoors April 19 Apr 19 – May 3
Transplant Outdoors June 7 Jun 7 – Jun 21
Direct Sow May 31 May 31 – Jun 21
Harvest August 16 Aug 16 – Oct 4

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors 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

1.5"/week · 2-3 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

123 days in Bear Lake County

Growing Tips for Watermelon in Bear Lake County

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

Common pests for Watermelon in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

Bear Lake County receives only 19" of rain annually. Watermelon needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 3-4 weeks early or direct sow after soil is warm. Plant on mounds with plenty of space. Check ripeness by looking for a yellow ground spot and dull thump when tapped.

Recommended Watermelon Varieties for Bear Lake County

Compact, early melons for shorter seasons

Sugar Baby (75d) Blacktail Mountain (70d) Golden Midget (70d)

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Watermelon in Bear Lake County, ID?

Bear Lake County is in Zone 5a with an average last frost of May 24. Plan your Watermelon 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.