Plant by your frost dates, not your zone
A hardiness zone says how cold winter gets. It can't tell you when to put tomatoes out. GrowDate Atlas takes the last-spring and first-fall frost dates NOAA already publishes for your nearest station and turns them into seed-starting, transplant, sowing and fall windows for 27 vegetables.
Concord, New Hampshire, built from NOAA station USW00014745 — the frost-free season, then every crop window inside it.
Tomatoes go out May 27 – Jun 10. Peas can go in Apr 15 – Apr 29. See the full Concord calendar
What a calendar here is made of
A named station and its real numbers
Every page shows the NOAA station, its coordinates and elevation, and the exact 1991–2020 normals it was built from.
Published timing rules, cited
Spring windows follow Colorado State Extension GardenNotes #720. Fall timing follows Purdue HO-66-W. Both are linked where they're used.
Missing data stays visible
Where NOAA can't compute a freeze normal, as in Phoenix or San Diego, the page says so instead of inventing a date.
A chart, a table and a download
Each city gets a 12-month planting chart and the same windows as a table. The planner prints and exports CSV.
Calendars by city
- Concord, New HampshireMay 13 to Sep 30
- Boston, MassachusettsApr 6 to Nov 8
- Burlington, VermontMay 4 to Oct 8
- Portland, MaineMay 1 to Oct 10
- Hartford, ConnecticutApr 24 to Oct 13
- Albany, New YorkApr 28 to Oct 10
- New York City (Central Park), New YorkApr 1 to Nov 18
- Philadelphia, PennsylvaniaApr 2 to Nov 10
- Pittsburgh, PennsylvaniaApr 24 to Oct 20
- Columbus, OhioApr 16 to Oct 27
- Cleveland, OhioApr 22 to Oct 31
- Detroit, MichiganApr 20 to Oct 24
Guides
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Method guides, October 16, 2026
Last Frost Date vs Hardiness Zone: Which One Sets Planting?
Last frost date vs hardiness zone: the zone is a winter-low number, the frost date is a planting number. Here is what each measures, with NOAA data.