When should I plant cilantro in ZIP 80012?

In ZIP 80012, the main cilantro target is around Apr 21, based on the representative Denver frost station and USDA zone 6a.

When should I start cilantro seeds indoors in 80012?

Cilantro is usually direct-sown for ZIP 80012. Use the Apr 21 planting window instead of starting it indoors.

Is this a guaranteed planting date?

No. GrowZone uses frost-date estimates, hardiness zones, and crop timing rules for planning. Local microclimates and current weather can shift the right date.

ZIP 80012 planting calendar

When to plant cilantro in Aurora, CO - Zone 6a

Q: When is the first frost in Aurora?

Aurora (ZIP 80012) has an average first fall frost around Oct 5, leaving about 153 frost-free days.

In ZIP 80012, plant cilantro around Apr 21; this uses the Denver frost station, USDA zone 6a, and cilantro timing rules.

Your Denver calendar has a 153-day estimated frost-free season. This estimate uses the representative Denver frost station, USDA zone 6a, and cilantro timing rules.

Source: denver-intl frost station, USDA zone 6a, last updated 2026-06-28. Verify locally before planting high-value crops because microclimates, current weather, and yard exposure can move the safe date.

USDA zone 6a Denver frost station Colorado State University Extension Updated 2026-06-28

Read the method

Answer first

When to start cilantro seeds indoors in Aurora

In ZIP 80012, cilantro is usually direct-sown around Apr 21 instead of started indoors.

Cilantro is normally direct-sown in Aurora. Use around Apr 21 as the outdoor planting window for ZIP 80012.

Seed starting schedule

Cilantro dates for Aurora, CO

Step	Date	How to use it
Direct Sow	April 21, 2026	Sow seed outside when the crop and soil can handle the window.

Last frost

When is the last frost in Aurora?

Aurora (ZIP 80012) has an average last spring frost around May 5.

First frost

When is the first frost in Aurora?

The average first fall frost is around Oct 5, giving about 153 frost-free days.

Season map

Cilantro windows by month

JanFebMarAprMayJunJulAugSepOctNovDec

Direct sow

Apr 21

Harvest

Jun 5

Frost watch

Aug 21

Reminder workflow

Every date has a next action

Direct sow cilantroApr 21

Last frost windowMay 5

First cilantro harvest windowJun 5

Last cilantro sowing targetAug 21

Signal	Value	Why it matters
Last frost estimate	May 5, 2026	Warm-season transplant risk starts falling after this window.
First frost estimate	October 5, 2026	Fall planting counts backward from this date.
Season length	153 days	Longer seasons can support succession crops.
Spacing	4-6 in	Airflow and root space affect yield.
Soil temperature	45 F+	Seeds and transplants stall in cold soil.

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Local data

Why this date changes by ZIP

Denver frost history and USDA zone 6a shift the safe planting window. GrowZone uses a local representative station instead of one national rule.

Colorado State University Extension is the kind of local source to verify against when a crop is expensive, weather is unusual, or your yard has a cold pocket.

Crop note

Cilantro timing notes

Sow small batches often because cilantro bolts in heat. Cilantro prefers sun to part shade, 4-6 in spacing, and soil near 45 F+.

For fall, count backward from Oct 5. A conservative last sowing target is around Aug 21.