Blog

When to Plant Watermelon in Grand County, UT

Watermelon

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.

Grand County, Utah is in USDA Zone 6b. The average last spring frost is April 19 and the first fall frost is October 13, giving you a growing season of approximately 177 days.

At an elevation of 5,415 feet, Grand County receives approximately 23.1 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Watermelon during the growing season.

Grand County, UT (Zone 6b) Moderate season
177 days
Last Spring Frost April 19
177 growing days
First Fall Frost October 13

Grand County Soil Profile

Soil Type

Loam

Soil pH

6.0-7.0

Drainage

Well Drained

How Much Watermelon to Grow

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

For a family of 4, plant approximately 4 watermelon plants in about 8 sq ft. In Grand County's 177-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Watermelon Planting Timeline — Grand County, UT

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors May 3 May 3 – May 17
Direct Sow April 26 Apr 26 – May 17
Harvest July 12 Jul 12 – Aug 30

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Direct Sow
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 6b

📆 Growing Season

177 days in Grand County

Growing Tips for Grand County

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.

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 Grand County, UT?

Grand County is in Zone 6b with an average last frost of April 19. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grand County, UT?

Grand County, Utah is in USDA Hardiness Zone 6b. The average last spring frost is April 19 and first fall frost is October 13.

🌱

Your Grand County Garden Planner — Free

A 22-page printable planner built for Grand 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Grand County, UT. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.