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When to Plant Cosmos in New Jersey

Cosmos (Cosmos bipinnatus) is an airy, feathery-foliaged cottage garden annual from Mexico that thrives on neglect. It produces delicate daisy-like blooms in shades of pink, white, and magenta from midsummer until frost. Cosmos is a prolific self-sower — once established in a garden it often returns year after year without replanting. Excellent habitat plant for beneficial insects.

New Jersey spans USDA hardiness zones 6b, 7a, 7b (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

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Find Your County

Click your county for exact Cosmos planting dates based on your local frost dates.

Hover over a county to see details. Click to view planting guide.

Cosmos Planting Calendar for New Jersey

Zone 6b ~205 day growing season · Full guide →

Last frost: April 3 · First frost: October 25 · 205 day season

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors April 3 Apr 3 – Apr 17
Direct Sow April 3 Apr 3 – Apr 24
Bloom June 12 Jun 12 – Sep 25
Zone 7a ~221 day growing season · Full guide →

Last frost: March 25 · First frost: November 1 · 221 day season

Activity When Date Range
Start Indoors February 25 Feb 25 – Mar 11
Transplant Outdoors March 25 Mar 25 – Apr 8
Direct Sow March 25 Mar 25 – Apr 15
Bloom June 3 Jun 3 – Sep 23
Zone 7b ~235 day growing season · Full guide →

Last frost: March 18 · First frost: November 8 · 235 day season

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors March 11 Mar 11 – Mar 25
Direct Sow March 11 Mar 11 – Apr 1
Bloom May 20 May 20 – Sep 23

Growing Tips for New Jersey

Direct-sow after last frost; cosmos germinates readily at 65-80°F in 7-10 days. Avoid rich soil — excess fertility produces lush foliage at the expense of blooms. Cosmos tolerates poor, dry soil exceptionally well. Pinch seedlings at 8 inches to encourage branching. Self-sows freely; allow some seed heads to mature and drop for a no-fuss perennial effect in warm climates.

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Frequently Asked Questions

When should I plant Cosmos in New Jersey?

Planting dates for Cosmos in New Jersey depend on your USDA zone. New Jersey spans zones 6b, 7a, 7b. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is New Jersey for planting?

New Jersey contains USDA hardiness zones 6b, 7a, 7b. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Last updated: June 2026.