When to plant garlic in Denver, Colorado

October 19 – October 26

Fall planting · typical Denver year

Climate basis: NOAA station Denver Water Dept, CO (USC00052223), 2 mi (3 km) from downtown Denver (ZCTA 80202 centroid), elevation 5228 ft, on the 1991–2020 climate normals. Plant garlic cloves from approximately the dates above, anchored to the median first fall 32°F freeze (October 12). One year in ten still freezes after May 13.

Last spring freezeApril 301-in-10 after May 13
First fall freezeOctober 121-in-10 before Sep 28
Frost-free season165 daysmedian at 32°F
Hard freeze, 28°Apr 18Oct 21kills even hardy greens
USDA zone6a-10 to -5°F winter low not frost timing

The Denver year

Fall plantingOct 19 – Oct 26
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 13
Garlic in Denver · freeze context from Denver Water Dept, CO, 1991–2020 normals.

Every method, with its sources

Fall planting

Oct 19 – Oct 26

Minnesota: plant cloves in the fall, usually one or two weeks AFTER the first killing frost (before the ground freezes). Harvest is the following summer. Anchored to the median first fall freeze (Oct 12). University of Minnesota Extension

Start seeds indoors

Not calculated

Garlic is grown from cloves planted in fall, not from seed or spring transplants.

Transplant outdoors

Not calculated

The cited extension guides do not time an outdoor transplanting window for this crop.

Direct-sow outdoors

Not calculated

The cited extension guides do not time direct sowing for this crop.

Variety assumption: Overwinters in the ground; bulbs are harvested the following summer.

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

This week, not a typical year:
Crop rule sources (1)

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