Loading planting windows
Germination timing based on current soil temperature readings from your nearest monitoring station.
These windows are computed from Lebanon's multi-year soil-temperature climatology and NOAA 1991-2020 frost normals, so they reflect this location rather than a regional average. Treat them as a starting plan and confirm with current readings.
The typical first freeze (32°F) near Lebanon is October 6, from NOAA 1991-2020 frost normals measured 3 miles away. Cool-season seedlings need about 42 days of root growth before that freeze, so counting back from it puts the last safe seeding day around August 25. Seed later than that and roots will not establish before dormancy; the seed usually survives winter, but germination and coverage suffer.
Cool-season grasses (tall fescue, Kentucky bluegrass, perennial ryegrass) germinate best when the 2-inch soil temperature stays between 50°F and 65°F. The ideal window is early to mid-spring, or early fall when soil cools back into this range. Fall seeding has less weed competition and more consistent moisture.
Warm-season grasses (Bermuda, zoysia, St. Augustine, centipede) need soil temperatures of65°F or higher for germination. These grasses are best seeded in late spring through early summer when soil has fully warmed.
Use a soil thermometer at 2 inches depth, measured mid-morning after the sun has warmed the surface. Take readings in several spots and average them. One warm day does not mean soil is ready; look for a sustained trend across 3–5 days.
Enter your city or ZIP code for real-time 2-inch soil temperatures from the nearest USDA monitoring station.