Summer annual grasses such as crabgrass require proper soil temperature and moisture to germinate and establish. Eighty percent of germination will occur when soil temperatures at the 0-2 inch depth are consistently between 60 and 70 F.

What is the best time to apply crabgrass preventer?

The best time to apply a crabgrass preventer will be when the soil temperature reaches 55-60 degrees Fahrenheit and holds that reading for a few days in a row.

What temperature do you apply pre-emergent?

Spring pre-emergent herbicide applications are used to prevent summer annual weeds. Summer annual weeds are both grassy and broadleaf types. For best results apply herbicides when the soil temperature is around 55 degrees or above for at least 36 to 72 hours (ideally this will be two weeks before seed germination).