Looking for a book i read a long time ago.

Hello, Im looking for a a book about a girl whoes gandparents were farmers. Its summer and she is working on her summer reading assignment, i think the book was a separate piece by john knowls. During the summer, her grandmother gets hurt or sick and cant run the farm machine and so at night she helps with the feilds. I read this book atleast 10 years ago. I also think she was a japanese immigrant. Thanks for you time