In "To Kill a Mockingbird," why can't Walter Cunningham pass the first grade?

The reason Walter Cunningham can't pass the first grade has a lot to do with his background. In the novel, when Miss Caroline's good deed falls flat, Scout explains that Walter is a Cunningham and that he comes from a proud family, even if he is poor. In other words, the Cunninghams don't take gifts lightly; they always pay for what they use. If they can't pay for it, they go without. This is why Walter refuses to take Miss Caroline's money to pay for a lunch he cannot afford.

Atticus tells Scout that Mr. Cunningham often pays him in produce and other gifts because he is cash poor. Because Walter often has to help his father in the fields, he has little time to concentrate on his studies. We get the idea that education takes a back seat to temporal and practical matters in the Cunningham household. The Cunninghams are more concerned about surviving hard times than in receiving an adequate education.

In fact, Mr. Cunningham himself is said to have trouble signing his name. With such an example, Walter can't help but harbor similar nonchalance towards his own studies. At dinner with the Finches one day, he assures Atticus that, even though he has to help his father with the crops every spring, "there’s another’n at the house now that’s field size.” This possibly means that one of Walter's siblings will soon be able to help out in the fields, providing Walter the extra time he needs to devote to his studies.