With the above average temperatures over the last few weeks, many questions have arisen again about when to apply the preemergence herbicide for crabgrass. As mentioned in the February 20 edition of Turf Tips, it is much better to apply early rather than late. It is still not too late to apply preemergence herbicide as crabgrass has not germinated over most of the state. We are just entering the “traditional” application timing as indicated by the gold flowering of forsythia (photo). Even on the outside chance that some crabgrass has already germinated in hotspots along walks in southern Indiana , the forecast with low temperatures in the teens should kill any young crabgrass. Applications of preemergence herbicide over the next week or two should still be very effective.
Send corrections, suggestions, and comments to biehlj@purdue.edu