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When to Plant Onion in Gloucester County, NJ

Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

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 Onion 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 (82 days to spare)
Start indoors: Feb 17 Transplant: Mar 24 🍅 Harvest: Jun 23 – Aug 11
Recommended (50%) ✓ Fits season (81 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: Jul 5 – Aug 23
Safe Start (90%) ✓ Fits season (81 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jul 28 – Sep 15

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
Onion needs ~2,152 GDD — county provides 4,530 GDD Excellent fit

Onion Planting Timeline โ€” Gloucester County, NJ

Onion Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 โ€“ Mar 15
Transplant Outdoors April 5 Apr 5 โ€“ Apr 19
Direct Sow March 22 Mar 22 โ€“ Apr 12
Fall Sowing September 3 Sep 3 โ€“ Sep 17
Harvest July 5 Jul 5 โ€“ Aug 23

Plant 1" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7a

Growing Season

221 days

Growing Tips for Gloucester County

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Level Up Your Garden

Frequently Asked Questions

When should I plant Onion in Gloucester County, NJ?

Gloucester County is in Zone 7a with an average last frost of April 5. Plan your Onion 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.

๐ŸŒฑ

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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Free download. Plan your entire garden season in minutes.

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.