Cold Temperatures Extend Application Timing for Crabgrass Preemergence Herbicides

Cold soil temperatures should extend timing for crabgrass preemergence herbicide applications.

Kevin Frank, Michigan State University Extension, Department of Plant, Soil and Microbial Sciences – April 16, 2020

Cold Temperature Gauge
Cold soil temperatures following a light snowfall on April 15, 2020. Photo by Kevin Frank, MSU.

The cold temperatures and even snow showers in many parts of Michigan this last week have really slowed down turfgrass growth and provided additional time for making crabgrass preemergence applications. According to GDDTracker, almost the entire Lower Peninsula is now in the optimum application window for crabgrass preemergence herbicides. Southern areas of the state are almost past the optimum application window but with the cold temperatures this week, soil temperatures have declined significantly. Soil temperatures at the Hancock Turfgrass Research Center in East Lansing, Michigan, have declined from a high of 57 degrees Fahrenheit on April 8, 2020, to a high of 45 on April 15.

Preemergence map