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When to Plant Watermelon in Delaware County, PA

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.

Delaware County, Pennsylvania is in USDA Zone 7b. The average last spring frost is April 16 and the first fall frost is October 24, giving you a growing season of approximately 191 days.

At an elevation of 1,094 feet, Delaware County receives approximately 38.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Watermelon during the growing season.

Delaware County, PA (Zone 7b) Moderate season
191 days
Last Spring Frost April 16
191 growing days
First Fall Frost October 24

Delaware County Soil Profile

Soil Type

Silt 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 Delaware County's 191-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Watermelon Planting Timeline — Delaware County, PA

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 23 Apr 23 – May 14
Harvest July 9 Jul 9 – Aug 27

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors 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 7b

📆 Growing Season

191 days in Delaware County

Growing Tips for Delaware 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 Delaware County, PA?

Delaware County is in Zone 7b with an average last frost of April 16. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Delaware County, PA?

Delaware County, Pennsylvania is in USDA Hardiness Zone 7b. The average last spring frost is April 16 and first fall frost is October 24.

🌱

Your Delaware County Garden Planner — Free

A 22-page printable planner built for Delaware County (Zone 7b). 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 Delaware County, PA. 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.