Site elevation, average temperature and precipitation during the first growing season of the study (NOAA, 2020). Dates of Pseudoroegneria spicata seeding, growing degree days and herbicide application dates. Cumulative growing degree days (GDD = sum of average daily temperature °C–temperature base 4.4°C between 1 March 2018 to 31 May 2018) for Pseudoroegneria spicata by planting date.
| Elevation, Temperature, and Precipitation | Belgrade | Corvallis West | Corvallis East |
|---|---|---|---|
| Elevation (m) | 1363 | 1096 | 1424 |
| Avg. Temp. °C (Hi / Lo., 2018 Mar–May) | 13 / −1 | 14 / 2 | 14 / 2 |
| Avg. Temp. °C (Hi / Lo., 2018 June–Aug.) | 27 / 8 | 26 / 8 | 26 / 8 |
| Avg. Precip., mm (2018 Mar–May) | 53.8 | 32.5 | 46.0 |
| Avg. Precip., mm (2018 June–Aug.) | 42.7 | 40.1 | 40.9 |
| Seeding Dates (day-month-year), and Cumulative Growing Degree Days (GDD) | |||
| Fall | 15-November-17 | 30-October-17 | 30-October-17 |
| Spring 1 | 21-April-18, 34.3 | 3-April-18, 20.9 | 3-April-18, 20.9 |
| Spring 2 | 3-May-18, 85.7 | 19-April-18, 47.6 | 19-April-18, 47.6 |
| Spring 3 | 17-May-18, 201 | 4-May-18, 118 | 4-May-18, 118 |
| Spring 4 | 31-May-18, 210 | 15-May-18, 338 | 15-May-18, 338 |
| Herbicide Application Dates (day-month-year) | |||
| Fall | 19-October-17 | 15-October-17 | 15-October-17 |
| Spring | Not applicable | 11-April-18 | 11-April-18 |