When to Plant Cosmos in New Mexico

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 Mexico spans USDA hardiness zones 6a, 6b, 7a, 7b, 8a, 8b (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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Click your county for exact Cosmos planting dates based on your local frost dates.

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Cosmos Planting Calendar for New Mexico

▸ Zone 6a ~193 day growing season · Full guide →

Last frost: April 10 · First frost: October 20 · 193 day season

Activity	When	Date Range
Start Indoors	March 13	Mar 13 – Mar 27
Transplant Outdoors	April 10	Apr 10 – Apr 24
Direct Sow	April 10	Apr 10 – May 1
Bloom	June 19	Jun 19 – Sep 25

▸ 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

▸ Zone 8a ~255 day growing season · Full guide →

Last frost: March 8 · First frost: November 18 · 255 day season

Activity	When	Date Range
Start Indoors	February 8	Feb 8 – Feb 22
Transplant Outdoors	February 22	Feb 22 – Mar 8
Direct Sow	February 22	Feb 22 – Mar 15
Bloom	May 3	May 3 – Sep 20

▸ Zone 8b ~276 day growing season · Full guide →

Last frost: February 25 · First frost: November 28 · 276 day season

Activity	When	Date Range
Start Indoors	January 28	Jan 28 – Feb 11
Transplant Outdoors	February 4	Feb 4 – Feb 18
Direct Sow	February 4	Feb 4 – Feb 25
Bloom	April 15	Apr 15 – Sep 16

Growing Tips for New Mexico

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.

Cosmos in Other States

Frequently Asked Questions

When should I plant Cosmos in New Mexico?

Planting dates for Cosmos in New Mexico depend on your USDA zone. New Mexico spans zones 6a, 6b, 7a, 7b, 8a, 8b. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is New Mexico for planting?

New Mexico contains USDA hardiness zones 6a, 6b, 7a, 7b, 8a, 8b. 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.

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