I highly recommend you check out this great website. They have wonderful info and resources to help educate and engage kids with gardening.
National Gardening Association offers the Web’s largest and most respected array of gardening content for consumers and educators, ranging from general information and publications to lessons and grants. Explore our Web site and discover a world of gardening possibilities. Kidsgardening.org is a resource of the National Gardening Association dedicated to providing content and resources specifically designed for use with children and in educational environments.