The rate of leaf development was used for detecting and evaluating growth responses of carnations to environmental factors. Studies were conducted in two separate greenhouses with different temperature, humidity, and soil moisture conditions. Quantitative morphological stages of leaf growth were recorded on a daily basis until buds formed at which time daily bud diam measurements were begun. The cumulative data were transformed into growth rates. Environmental data were obtained daily. Lags in the effect of each environmental factor on growth were obtained by simple correlation analyses using environmental data on the day of growth and each of five previous days. Multiple regression analyses using leaf growth rate or bud growth rate as the dependent variable and environmental data with appropriate lags as independent variables were conducted to determine the relationship of the various environmental factors to growth rate. Equations were developed to predict plant growth under varying environmental conditions.