When do I apply crabgrass preventative?
Kalamazoo County Michigan
Timing for pre-emergent products is right on the edge of being too late in the Kalamazoo area. If you are going to apply preventative products, do so as soon as possible to still have it be effective.
Pre-emergent crabgrass herbicides should be applied when soil temperatures are around 50-55 F. (Crabgrass germinates when the soil temperatures are around 60-70 F at 0 – 2” deep so products should be applied before soils reach that temperature.) A good environmental indicator for best timing of pre-emergent products is when the yellow flowers of forsythia bushes are blooming.