Mary Call is the 14-year-old narrator and acting head of the Luther family. Living in a rural valley in the Appalachian mountains, she takes on immense responsibility due to her father's severe illness. She is fiercely determined, highly resourceful, and values education over everything else. She relies heavily on a wildcrafting guide left by her late mother to support her siblings.

Devola is the 18-year-old eldest sibling of the Luther family. Though her father and Mary Call consider her slow-witted, she is highly capable at cooking and maintaining the household. She possesses a gentle, maternal nature and dreams of living a comfortable life with hot water and electricity.

Romey is the 10-year-old brother in the Luther family. He is deeply observant of the natural world and tries his best to fulfill the traditional role of a man in the household. He frequently works alongside Mary Call, helping to gather wild herbs to sell at the local store.

Kiser Pease is the 30-year-old bachelor who owns the land where the Luther family sharecrops. He lives a lonely, solitary life and frequently attempts to court the eldest Luther sister, despite her father's strict prohibition. Though he holds significant financial power over the Luthers, his occasional illnesses leave him vulnerable.

Roy Luther is the patriarch of the Luther family and a sharecropper on Kiser Pease's land. Suffering from a severe and worsening illness, he exacts strict promises from his second daughter to ensure the family stays together without accepting charity. He is fiercely proud and refuses to involve doctors or preachers in his life.

Ima Dean is the youngest sibling of the Luther family. She is largely protected from the heavy burdens of survival by her older siblings. She finds ways to entertain herself in their impoverished circumstances and brings a sense of youth and innocence to the household.

Mr. Connell is the cheerful owner of the local General Store. He encourages the Luther siblings in their wildcrafting efforts and purchases their medicinal roots and leaves. He serves as a friendly, supportive adult figure in their town.

Mrs. Connell is the nosy and openly judgmental wife of the General Store owner. She frequently pries into the Luther family's business, criticizing their father's pride and suggesting the children should rely on charity or orphanages.

Miss Breathitt is the principal and teacher at the school the Luther children attend. She values cleanliness and curiosity, viewing education as a vital tool for living well and escaping poverty.

Goldie Pease is Kiser's sister who travels from Georgia to the valley. She is crafty and views the Luther family with deep suspicion, creating a significant obstacle for them regarding their living arrangement.