How this calculator works
Each crop has a "weeks before frost" or "weeks after frost" figure copied from a named university extension guide, with the date we checked it. The calculator only does the date arithmetic from your own frost date; it does not estimate your frost date for you, because a ZIP code alone is not precise enough to publish as fact.
Crops covered so far
- Tomatoes, checked 2026-09-27 against Growing tomatoes in home gardens — University of Minnesota Extension
- Peppers, checked 2026-09-27 against Growing peppers in home gardens — University of Minnesota Extension
More crops are added as each is verified against a named source.