I get the feeling this book isn’t really meant for the audience it’s claiming to be for — I don’t think it’s so much a kids’ book as it is a book for parents who want to raise eco-friendly kids.  Kids who are interested in gardening in the city are going to be more interested in how-tos.  This is more like an anthropological work on the good that gardens can bring to urban environments.  It’s a nicely constructed book, but not likely to have much appeal beyond a niche audience.