GrowZone

ZIP 80202 · Denver, CO · USDA zone 6a

In ZIP 80202, plant tomatoes around May 12.

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

Read the method
Start tomatoes indoorsMar 24
Last frost windowMay 5
Transplant tomatoesMay 12
Last tomatoes sowing targetJul 19
First tomatoes harvest windowJul 29
SignalValueWhy it matters
Last frost estimateMay 5, 2026Warm-season transplant risk starts falling after this window.
First frost estimateOctober 5, 2026Fall planting counts backward from this date.
Season length153 daysLonger seasons can support succession crops.
Spacing18-24 inAirflow and root space affect yield.
Soil temperature60 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

Tomatoes timing notes

Harden seedlings off for a week before transplanting. Tomatoes prefers full sun, 18-24 in spacing, and soil near 60 F+.

For fall, count backward from Oct 5. A conservative last sowing target is around Jul 19.