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When to Plant Watermelon in Gloucester County, NJ

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.

Gloucester County, New Jersey is in USDA Zone 7a. The average last spring frost is April 5 and the first fall frost is November 12, giving you a growing season of approximately 221 days.

At an elevation of 735 feet, Gloucester County receives approximately 49.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94ยฐF, providing good warmth for Watermelon during the growing season.

Gloucester County, NJ (Zone 7a) Long season
221 days
Last Spring Frost April 5
221 growing days
First Fall Frost November 12

Gloucester County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (89 days to spare)
Start indoors: Feb 24 Transplant: Apr 7 🍅 Harvest: Jun 16 – Aug 4
Recommended (50%) ✓ Fits season (88 days to spare)
Start indoors: Mar 8 Transplant: Apr 19 🍅 Harvest: Jun 28 – Aug 16
Safe Start (90%) ✓ Fits season (88 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Jul 21 – Sep 8

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 102 gal / 100 sq ft
Watermelon needs ~1,742 GDD — county provides 4,530 GDD Excellent fit

Watermelon Planting Timeline โ€” Gloucester County, NJ

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 โ€“ Mar 22
Transplant Outdoors April 19 Apr 19 โ€“ May 3
Direct Sow April 12 Apr 12 โ€“ May 3
Harvest June 28 Jun 28 โ€“ Aug 16

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 7a

Growing Season

221 days

Growing Tips for Gloucester 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Watermelon in Gloucester County, NJ?

Gloucester County is in Zone 7a with an average last frost of April 5. Plan your Watermelon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Gloucester County, NJ?

Gloucester County, New Jersey is in USDA Hardiness Zone 7a. The average last spring frost is April 5 and first fall frost is November 12.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Gloucester County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

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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 Gloucester County, NJ. Local conditions may vary. Last updated: April 2026.