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When to Plant Sunflower in Sussex County, NJ

Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

Sussex County, New Jersey is in USDA Zone 6a. The average last spring frost is March 29 and the first fall frost is November 12, giving you a growing season of approximately 228 days.

At an elevation of 174 feet, Sussex County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Sunflower during the growing season.

Sussex County, NJ (Zone 6a) Long season
228 days
Last Spring Frost March 29
228 growing days
First Fall Frost November 12

Sussex County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (95 days to spare)
Start indoors: Jan 28 Transplant: Apr 8 🍅 Harvest: Jun 17 – Aug 5
Recommended (50%) ✓ Fits season (95 days to spare)
Start indoors: Feb 1 Transplant: Apr 12 🍅 Harvest: Jun 21 – Aug 9
Safe Start (90%) ✓ Fits season (104 days to spare)
Start indoors: Feb 12 Transplant: Apr 23 🍅 Harvest: Jul 2 – Aug 20

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
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Sunflower needs ~1,232 GDD — county provides 3,306 GDD Excellent fit

Sunflower Planting Timeline โ€” Sussex County, NJ

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 1 Feb 1 โ€“ Feb 15
Transplant Outdoors April 12 Apr 12 โ€“ Apr 26
Direct Sow April 5 Apr 5 โ€“ Apr 26
Harvest June 21 Jun 21 โ€“ Aug 9

Plant 1" deep ยท 18" apart ยท Rows 30" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 6a

Growing Season

228 days

Growing Tips for Sussex County

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Sunflower in Sussex County, NJ?

Sussex County is in Zone 6a with an average last frost of March 29. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Sussex County, NJ?

Sussex County, New Jersey is in USDA Hardiness Zone 6a. The average last spring frost is March 29 and first fall frost is November 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Sussex County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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