Q.Frost Dates & Planting Timing
What is a killing frost vs. a light frost?
A.
A killing frost is 28°F or below — kills most annual plants and damages woody perennials. A light frost is 29-32°F — damages tender vegetation but doesn't kill cold-hardy plants. A hard freeze is 24°F and below — kills nearly everything not specifically winter-hardy.
Frost-date pages show probability tables at all three thresholds (28°F, 32°F, 24°F). Use 32°F for sensitive transplants, 28°F for the agricultural standard, 24°F for tree-crop dormancy planning.