Sources & citations
Every timing entry on the site cites a university extension source (or, where we couldn't find a direct citation for the exact grass-zone combination, names the physiology rule we used to interpolate). Below, the source list is grouped by grass and then by task. Each link points to the extension publication's landing page; the per-page entries link to the specific reference.
Kentucky Bluegrass
- Weed Control
Tall Fescue
- Fertilize
- Weed Control
Fine Fescue
- Weed Control
Perennial Ryegrass
- Weed Control
Bermuda Grass
- Weed Control
Zoysia
- Weed Control
St. Augustine
- Weed Control
Centipede
- Fertilize
- Weed Control
Bahia
- Weed Control
Buffalo Grass
- Weed Control
On “inferred” entries
A handful of grass-zone-task combinations don't have a direct extension publication: usually because the grass species is marginal in that zone, or the task is uncommon (e.g. winter rye overseed in zone 6). For those entries, the page surfaces an amber caveat band noting the source is a grass-physiology rule, not a direct citation. Treat those windows with extra skepticism.