Taking pictures of your garden is a great activity for kids. To learn about gardening for kids you might want to check out these books at your local library or on Amazon.
Jam and Jelly: A Step-by-Step Kids Gardening and Cookbook (Grow Your Own Ingredients) by Cassie Liversidge
Gardening Projects for Kids: Fantastic ideas for making things, growing plants and flowers, and attracting wildlife to the garden, with 60 practical projects and 500 photographs by Jenny Hendy
Gardening Lab for Kids: 52 Fun Experiments to Learn, Grow, Harvest, Make, Play, and Enjoy Your Garden by Renata Brown
Oh Say Can You Seed?: All About Flowering Plants (Cat in the Hat’s Learning Library) by Bonnie Worth and Aristides Ruiz
Don’t forget to take pictures of the kids doing their gardening. It will be a memory for both of you!