Mrs. Gearson wants Editha to take off the black clothes because she sees them as a symbol of sadness and mourning that is preventing Editha from moving on from her grief. Mrs. Gearson believes that Editha needs to heal and come to terms with her loss in order to move forward and live a full life. By taking off the black clothes, Mrs. Gearson hopes Editha can start the process of moving on and embracing the joys of life.