The calendar on every page of this site is data, not prose. For each state we keep the last spring frost and first fall frost published by the state’s extension service or NOAA, the USDA hardiness zones, the lawn zone (cool-season, warm-season or transition) and the annual rainfall at a named reference station.
The month-by-month windows come from published extension calendars (Clemson Cooperative Extension maintenance calendars for each grass species, UC IPM Pest Notes for roses, Clemson HGIC for hydrangeas and tree planting), narrowed to each state’s own growing season. A task that assumes growth — mowing, fertilizing, seeding, aerating — is never shown outside the months between a state’s last and first frost.
Where a state has no reliable frost, the site says so. Where a source is missing, the cell stays empty rather than guessed.