Crabgrass Pre-emergence Timer

Suggested Timing: 250-500 GDDSource:Calhoun – Michigan State University (2004)

Germination of summer annual grasses (crabgrass, goosegrass, foxtail) occurs when soil temperatures in the top two inches range from 60-70 degrees F. Preemergence herbicides need to be present in the soil before germination begins, usually when soil temperature are in the 50-55 degrees F range. While soil temperature monitoring is ideal, this model uses growing degree days to approximate the optimum timing for pre-emegernce herbicide applications.