Sunflowers Planting Dates in Colorado

Usual sunflowers planting and harvest periods in Colorado, shown as ranges with their source. Use them to frame a plan, then adjust for your own frost dates and soil temperature.

Sunflowers dates in Colorado
Activity	Window	Source	Last verified
Planting	May 19 to Jul 1 usual (most active May 25 to Jun 23)	source	2026-11-11
Harvest	Sep 27 to Nov 26 usual (most active Oct 6 to Nov 15)	source	2026-11-11

Sunflowers calendar for Colorado
Item	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Planting					Planting window, most active in May	Planting window, most active in June	Planting window in July
Harvest									Harvest window in September	Harvest window, most active in October	Harvest window, most active in November

What these dates mean in Colorado

Planting usually runs about 44 days, from May 19 to Jul 1.

That start date is about 5 days later than the middle of the 9 places in this data set that report sunflowers planting dates (May 14).

Harvest usually runs about 61 days, from Sep 27 to Nov 26.

From the start of the planting window to the start of the harvest window is about 131 days in Colorado, a rough guide to how long the crop occupies the bed or field.

Frost-date caveat: these are published ranges for Colorado. A northern or high-elevation site will run later than a southern or low one, and a cold wet spring can push planting past the window. Frost dates and local conditions vary; NASS state-level usual dates from 20-year progress data (Oct 2010 edition), begin ~5% and end ~95% complete. Check your last spring frost and soil temperature, and confirm with your county extension office.

Related guides

Sunflowers dates in other places

Other crops in Colorado

Last reviewed: November 2026. Source: USDA NASS, Field Crops Usual Planting and Harvesting Dates (October 2010 edition, copy hosted by Cornell University Mann Library). Dates are the usual start and end of the period when about 5% to 95% of the crop is planted or harvested, from long-run state progress data. They are historic averages, not a forecast.