What is the idea that bud is talking about

I'm not exactly sure about the pages but in chapter 9 Bud reads a book about the Civil War given to him by the kindly librarian. Bud says that ideas germinate in him like seeds; they begin as tiny seeds and grow into giant trees.

not sure about the pages but says that the ideas germinate in him like seeds ; they begin as tiny seeds and grow into gaint trees.