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When to Plant Amaranth in Colorado

Amaranth is an ancient grain crop with edible leaves and seeds, rich in protein and micronutrients. It thrives in warm conditions and is drought-tolerant once established.

Colorado spans USDA hardiness zones 3b, 4a, 4b, 5a, 5b, 6a, 6b (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

Find Your County

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

Amaranth Planting Calendar for Colorado

Zone 3b ~135 day growing season · Full guide →

Last frost: May 10 · First frost: September 22 · 135 day season

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 24 May 24 – Jun 14
Harvest August 30 Aug 30 – Oct 4
Zone 4a ~145 day growing season · Full guide →

Last frost: May 6 · First frost: September 28 · 145 day season

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors May 27 May 27 – Jun 10
Direct Sow May 20 May 20 – Jun 10
Harvest August 26 Aug 26 – Oct 14
Zone 4b ~155 day growing season · Full guide →

Last frost: May 1 · First frost: October 3 · 155 day season

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 15 May 15 – Jun 5
Harvest August 21 Aug 21 – Oct 9
Zone 5a ~166 day growing season · Full guide →

Last frost: April 25 · First frost: October 8 · 166 day season

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest August 8 Aug 8 – Sep 26
Zone 5b ~178 day growing season · Full guide →

Last frost: April 18 · First frost: October 13 · 178 day season

Activity When Date Range
Start Indoors February 21 Feb 21 – Mar 7
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest August 1 Aug 1 – Sep 19
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 February 13 Feb 13 – Feb 27
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 17 Apr 17 – May 8
Harvest July 24 Jul 24 – Sep 11
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 February 6 Feb 6 – Feb 20
Transplant Outdoors April 17 Apr 17 – May 1
Direct Sow April 10 Apr 10 – May 1
Harvest July 17 Jul 17 – Sep 4

Growing Tips for Colorado

Direct sow after last frost when soil is warm. Thin seedlings to 18 inches apart. Harvest leaves when young and tender; harvest seeds when flower heads begin to dry.

Frequently Asked Questions

When should I plant Amaranth in Colorado?

Planting dates for Amaranth in Colorado depend on your USDA zone. Colorado spans zones 3b, 4a, 4b, 5a, 5b, 6a, 6b. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Colorado for planting?

Colorado contains USDA hardiness zones 3b, 4a, 4b, 5a, 5b, 6a, 6b. 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: April 2026.