Crabgrass preemergence
Forsythia bush on MSU’s campus in the very early stages of bloom, taken March 13, 2020. Blooming forsythia bushes are a good environmental indicator for preemergence timing. Photo by Kevin Frank, MSU.

Timing crabgrass preemergence applications in spring

Spring is off to a slow start this year but there are always questions regarding the optimum timing for applying crabgrass preemergence herbicides. There are several different methods used for determining the optimum application timing from tracking growing degree days (GDD) to looking for forsythia bush flower bloom. One system used by both professional turfgrass managers and do-it-yourselfers to determine application timing is to track GDDs using the website GDDTracker.

Read the full article by Kevin Frank, Michigan State University Extension, Department of Plant, Soil and Microbial Sciences.