State agricultural overview

Colorado crop calendar.

Zone 5b
Range 3a to 7a
145-day season
Last frost May 10
First frost October 5

16 primary crops with planting windows for Colorado. Calendar timing is anchored to 5b dominant hardiness zone and a 145-day growing season — verify against Colorado State University Extension for variety- and county-specific guidance.

Row Crop · Colorado

Corn
primary
Spring: May 10 – May 31
Soybeans
primary
Spring: May 24 – June 14
Sunflowers
primary
Spring: May 17 – June 14
Winter Wheat
primary
Fall: September 28 – October 19
Grain Sorghum
secondary
Spring: May 31 – June 28
Cotton
trial
Spring: May 24 – June 14

Vegetables · Colorado

Cucumbers
primary
Spring: May 24 – June 28
Peppers
primary
Spring: May 31 – June 21
Potatoes
primary
Spring: April 26 – May 17
Fall: July 22 – August 6
Pumpkins
primary
Spring: May 31 – June 28
Sweet Corn
primary
Spring: May 10 – June 14
Tomatoes
primary
Spring: May 24 – June 14

Forages · Colorado

Alfalfa
primary
Spring: May 3 – May 31
Fall: August 6 – August 21
Clover
primary
Spring: April 19 – May 17
Fall: August 6 – August 21

Cover Crops · Colorado

Brassicas
primary
Fall: July 22 – August 6
Buckwheat
primary
Spring: July 5 – August 2
Cereal Oats
primary
Spring: May 3 – May 31
Fall: August 6 – August 21
Winter Rye
primary
Fall: September 28 – October 19

Frost & extension reference

Colorado climate anchors.

Last frost

May 10

First frost

October 5

Growing season

145 days

Hardiness zone

Colorado county-level frost dates →Colorado State University Extension →

Colorado planting timing. Live alerts.

Bield: Farm ties weather and soil-temperature stations in your county to crop planting thresholds — get notified the day soil temp clears your target window.

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