Research was conducted using the Soil-Plant-Atmosphere-Research (SPAR) units at Mississippi State University, Starkville, MS to investigate temperature effects on warm- and cool-season turfgrasses. Data collected include clipping yield, total root biomass, and relative chlorophyll index (RCI). Cultivars and species in the study included: ‘Latitude 36’, ‘Tifway’, ‘MSB-285’, and ‘TifEagle’ bermudagrass, ‘Meyer’ zoysiagrass, ‘Penn A1/A4’ and ‘Penncross’ creeping bentgrass, ‘Midnight’ Kentucky bluegrass, ‘Fiesta 4’ perennial ryegrass, and ‘Falcon V’ tall fescue. Grasses were grown in the SPAR units at varying day/night temperature regimes. Clipping yield was collected every three days, and regression was used to determine the temperature at which clipping yield equaled zero. Root biomass was collected at the conclusion of the trial, while RCI was taken once weekly. Base temperature for warm-season grasses ranged from 12.5 to 13.2°C. Determined optimum temperatures ranged from 31.8 to 36.1°C for warm-season turfgrasses and 18.8 to 20.6°C for cool-season turfgrasses.