In this experiment, the estimated Tmin ranged from −3.9 to13.8◦C, which indicates the range of thermal sensitivity among the different species and cultivars studied. Blanchard and Runkle (2011) observed a similar variability in temperature responses among 18 species of annual ornamentals. The estimated Tmin values here are generally within ±2◦C of those estimated in previous studies for the same species, but at times different cultivars. For example, our Tmin estimated for snapdragon and geranium was 2.0 and 0.7–1.5◦C higher, respectively, than that estimated by Blanchard (2009). Pramuk and Runkle (2005b) and Moccaldi and Runkle (2007) estimated Tmin for impatiens and marigold at 7.5 and −3.0◦C, respectively, which was 0.3 higher and 1.7◦C lower than our estimate s of 7.2 and −1.3◦C, respectively