There are several websites that maintain extensive lists of literature about gardening, food systems and ecology. Here is a summary of several lists to explore!
http://www.pareadysetgrow.org/book-list/
https://jmgkids.us/bookawards/
https://www.weareteachers.com/best-gardening-books-for-kids/
https://www.teachingexpertise.com/classroom-ideas/gardening-books-for-kids/
https://shrinkthatfootprint.com/childrens-picture-books-about-sustainability/
https://oklahoma.agclassroom.org/resources_classroom/books/
https://bookroo.com/explore/books/topics/agriculture
https://extension.unr.edu/publication.aspx?PubID=2918
And a NEW addition to our list, highlighting the benefits of gardening for all ages: https://www.billyoh.com/resource/benefits-of-gardening-older-adults

Planting a Rainbow, Lois Ehlert
In this perennial classic by Caldecott Honor–winning author Lois Ehlert, little ones learn the colors of the rainbow as they watch plants grow in a beautifully vibrant garden.
Celebrate Earth Day, spring, and the basics of gardening while improving color recognition with Lois Ehlert’s Planting a Rainbow!
Age Range: 4-8 years

Chirri & Chirra in the Tall Grass, Kaya Doi
Identical Japanese twins Chirri and Chirra shrink to the size of insects when they ride their bicycles into a patch of tall grass. Their tale presents to children the connections between food and nature through an up-close view of the lives of small creatures. They come across friendly, hardworking bumblebees and beetles, sharing honey sponge cake and freshly squeezed mixed-leaf juice.
Age Range: 2-8 years

You Are What You Eat, Serge Bloch
Mealtime should be a piece of cake, but Roger eats like a bird. This drives his mother bananas because he really should have three square meals a day. Children will find the sayings puzzling at first, but Bloch’s images make everything clear and will leave readers of all ages pleased as punch.
Age Range: 5+ years

How Did That Get in My Lunchbox? by Chris Butterworth
One of the best parts of a young child’s day is opening a lunchbox and diving in. But how did that delicious food get there? From planting wheat to mixing dough, climbing trees to machine-squeezing fruit, picking cocoa pods to stirring a vat of melted bliss, here is a clear, engaging look at the steps involved in producing some common foods. Health tips and a peek at basic food groups complete the menu.
Age Range: 3-7 years