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Boulder, CO planting calendar

When to plant vegetables in Boulder, CO (USDA hardiness zone 6a). Typical last spring frost around May 6, 2026 9 days year to year), first fall frost around Oct 5, 202611 days).

Playing it safe? Spring frost holds off until about May 17, 2026 in roughly 9 years out of 10 — a good target for tender crops like tomatoes and peppers.

Want exact dates for your address, a drag-and-drop bed layout, and reminders when it’s time to sow? Enter your ZIP:

Or get a printable Boulder calendar and sowing reminders by email:

Still time to plant

As of today, these crops can still reach harvest before Boulder, CO’s first frost (~Oct 5, 2026) — fastest first.

Month by month in Boulder, CO

January

February

March

April

May

July

August

Understand your frost dates

Frost dates are NOAA 1991–2020 climate normals for a representative location in Boulder, CO (covering 5 ZIPs); your exact dates depend on your address. Schedules are guidance, not guarantees.