When did Mr. Cunningham deliver hickory nuts?

In chapter 2, Scout attempts to stick up for Walter Cunningham Jr. during lunch and does a poor job of explaining his home life to her new teacher, Miss Caroline, who is not from Maycomb County. Scout naively assumes that Miss Caroline is familiar with the Cunninghams and their frugal ways. After poorly explaining to Miss Caroline that Walter is a Cunningham and will never take anything he cannot return, Scout recalls her special knowledge of the Cunningham tribe from their interactions with Atticus. Scout mentions that Walter's father did not have the money to pay Atticus to handle his entailment and proceeded to pay her father back using natural products and resources from his farm. Scout recalls finding a pile of stovewood in their backyard and later discovering a sack of hickory nuts on their back steps. Mr. Cunningham also gave Atticus a crokersack full of turnip greens to fully pay him back for his services. When Scout asks Atticus why Mr. Cunningham paid him back using products from his farm instead of currency, Atticus tells his daughter,

Because that’s the only way he can pay me. He has no money. (Lee, 21)

In chapter 2 of To Kill a Mockingbird, Scout is attempting to explain to Miss Caroline why Walter Cunningham will not accept money for lunch. As her demonstration of why he will not accept Miss Caroline's quarter, Scout offers the explanation of, "Miss Caroline, he’s a Cunningham." This explanation makes sense to everyone except Miss Caroline.
Scout proceeds to enlighten Miss Caroline to the ways of the Cunninghams. Scout explains, "The Cunninghams never took anything they can’t pay back." Walter's father, Mr. Cunningham, is one of Atticus's clients. After a meeting once in which Atticus provides his services for Mr. Cunningham, Mr. Cunningham says, "Mr. Finch, I don’t know when I’ll ever be able to pay you." Atticus assures Mr. Cunningham not to worry himself about payment. However, while Mr. Cunningham cannot pay in money, he manages to pay Atticus with other means. Once he pays in stovewood delivered to Atticus's house. Scout recalls the next payment is in the form of hickory nuts. When Scout asks her father why Mr. Cunningham pays this way, Atticus responds, "Because that’s the only way he can pay me. He has no money."