Oh, I really like that idea. So easy to do. And it’d be great for all kinds of root vegetables! Carrots, parsnips, cassava, taro, burdock. Actually, especially burdock. Very healthy but a real pain to try and dig up.
As a random aside, BTW, sweet potatoes are a great plant to grow because every last part of the plant is edible! The leaves apparently make quite a good spinach substitute. Sweet potatoes can contain a lot of oxalate though, so be sure to cook them thoroughly. Adding some lemon juice helps too.