From the Bookshelf of Baltimore County Public Library Summer Reading BCPL SRC …

[close] I love what the onion symbolizes in the book. It symbolizes something good and healing. Onions, when you think about it, are not the most glamorous of foods. Along with carrots and potatoes, they grow in the dirt, and the edible part actually grows underground. The onion can symbolize one moral of Holes in that, like peeling an onion, you have to “dig deeper” to get to what really matters.