Q: Look at what happened to my crabgrass: couple of weeks ago it just died. Whataya think happened?
A: This is a natural phenomenon. Crabgrass is sensitive to day length, so as days get shorter after June the plants set seed, drop them, and then gradually stop growing. Crabgrass dies in fall, thus giving bare spots in which annual bluegrass and other winter weeds can germinate.
That’s a quick summary of why it’s important to control crabgrass and why you should apply a pre-emergent on March 1 and September 15 each year.
Put out a pre-emergent if you haven’t already and fertilize the centipedegrass in May and June next year to speed its coverage of the bare spots.