Tough overseeding weather in Palm Springs in 2020
View Larger
Overseeding while the bermudagrass continues to grow results in competition between the cool season grass seedlings and the warm season base. This graph illustrates the sum of cool season growth potential (CGP) minus warm season growth potential (WGP) starting September 1, 2020. If WGP exceeds CGP, the slope of the line will be negative. When the CGP exceeds WGP, the line flattens out and begins to turns up (positive slope). The lower the line drops before truning upward and the date when the line begins to turn in favor of the cool season grasses provides a rough idea of how easily the cool season grasses will establish in the bermudagrass base before cold weather slows the growth of cool season seedlings. Overseeding before the date when the line turns upward increases the likelihood that the cool season grass seed will struggle in competition with the bermudagrass base. The date when this upswing occurred was after October 20th in 2020 - later than 9 of the past 10 years. Overseeding before this date increases the likelihood of slower cool season stand establishment caused by bermudagrass competion for light and nutrients.
