Crabgrass explosion

Asked September 3, 2015, 7:22 PM EDT

My lawn has exploded this late summer with an abundance of crabgrass. Previous years, I have had no trouble with this weed. Was the over abundance of rain early this summer a major issue in this? What can I do this fall and next year to defeat this unsightly weed?

Henry County Illinois

1 Response

Yes you are right, the excess rain this spring in some areas diluted and reduced the effectiveness of crabgrass products of the type that suppresses crabgrass seed germination (so-called pre-emerge types).

It is too late to use a post emergent herbicide this year. The crabgrass is too well established. However, the crabgrass will die off this fall. You can do some reseeding this fall to fill in where the desirable grass has died out.

Plan on using the pre-emergence herbicide next spring. In years with excessive rainfall, a second lighter application of the same pre-emergence herbicide may be needed. If the crabgrass is already sprouting switch to a post emerge crabgrass material applied before the crabgrass gets too big ( more than 3 or 4 leaves).