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Zone 3b planting calendar

When to start vegetables in USDA hardiness zone 3b. Typical last spring frost around May 17, 2027 (±10 days year to year), first fall frost around Sep 26, 2027 (±9 days). Based on 235 ZIP codes in the zone — exact dates vary by location.

Playing it safe? Spring frost holds off until about May 29, 2027 in roughly 9 years out of 10 — a good target for tender crops like tomatoes and peppers.

Zone 3b covers a lot of ground. Enter your ZIP for frost dates from your nearest weather station and a month-by-month calendar:

Month by month in zone 3b

February

March

April

May

June

August

Exact indoor-sow, transplant, and direct-sow windows for zone 3b’s most-planted vegetables.

Where these dates come from

Frost dates for zone 3bare NOAA 1991–2020 climate normals from a representative location (Hannah, ND). A hardiness zone spans thousands of miles, so no single station speaks for all of it. The guide to zones and frost dates covers what that means for your timing.

Your exact dates depend on your address and microclimate. Schedules are guidance, not guarantees.