The slats on some platform beds are easily adjustable, particularly if the slats don’t attach to the platform bed’s side rails and instead rest on the lip. You can move these slats closer together to provide extra support and firmness to the mattress, or you can move them farther apart to give a bit more softness and sag to the bed. Check your platform bed’s care instructions to see if your model’s slats are easily adjusted by hand or with the use of simple tools.