Jim Arnosky is a great author and illustrator. He does all nature books. His pictures are detailed and accurate. He is also the author of the 'Crinklefoot' books. 'Raccoons and Ripe Corn' is written very simply and a very young child, 12-24 months, would enjoy listening to it. It is very short. Most of his books are available in paperback, although if you see a hardback library edition, snag it. The Crinklefoot books are written for elementary students.
Robert McCloskey wrote a number of classic children's picture books. Probably his best known one is 'Make Way for Ducklings'. He likes to write about children living on the Maine coast. These are great stories for 3-4 year olds.
'Linnea in Monet's Garden' is a combination of nature and art books. The story is by Christina Bjork and Lena Anderson and tells of a girl who visits Monet's Garden and learns about the garden and Monet as well.
These same artists wrote a practical book on window sill gardening. It is well illustrated and gives very simple yet practical advice of things to try in gardening indoors.