put to bed

Put to bed means to settle something conclusively or complete it.

A newspaper editor puts an issue to bed when it's finalized for printing.

You might put a rumor to bed by disproving it, or put a project to bed by finishing the last details.

The phrase also retains its literal sense of helping someone—usually a child—get into bed for sleep: I need to put the kids to bed before the babysitter arrives.