DOUBLE TAP TO ZOOM WITH PHONE OR TABLET of responding quickly and accurately to germs, it reacts slowly, leaving you open to more frequent and severe illness. And when kids don’t get exposed to enough dirt, their immune systems start making the sort of serious mistakes that can lead to autoimmune illnesses, allergies, and asthma. When your immune system is exposed to plenty of dirt on a regular basis starting when you’re very young, it gets the regular workouts it needs to build up defenses and stay ready for action. (2009, 101) Given this evidence, it makes sense that all children, from infancy on, should play outside, touch plants, and dig in the soil. We should not be afraid if they get their hands and the rest of their bodies dirty. It doesn’t hurt us to eat a little dirt. It may just make us healthier in the long run. Children Need Time Outdoors Over the past decades, there has been an effort to make playgrounds safer and easier to maintain. Unfortunately, as a result, many outdoor play spaces became sterile, and some completely devoid of nature. Grass and trees have often been removed to clear space for large pieces of climbing equipment and the resilient ground cover that must surround the equipment. Sometimes play- grounds are completely comprised of resilient ground cover and man-made surfacing rather than natural materials. In these spaces, children have little opportunity to connect with nature. Nevertheless, the movement toward more natural play environments for young children is strong and growing. Recognition that these fabricated indus- trial environments are not serving children’s needs, along with concern that natural spaces are disappearing, is producing a movement to connect children with nature. One example has been the development of the Nature Action Collaborative for Children (NACC), which has sponsored the Working Forum on Nature Education, beginning in 2006. NACC is an interdisciplinary group comprised of sixteen hundred members from six continents, including early childhood educators, environmental educators, health specialists, landscape architects, and environmental activists. Working groups of NACC have various goals, one being to create natu- ral play spaces for children in preschool settings, schools, and communities. Nature Explore, a collaboration of the Arbor Day Foundation and Dimensions Educational Research Foundation, has been a leader in this movement and a sponsor of the Working Forum on Nature Education. Nature Explore defines a set of principles to use in designing an outdoor classroom, provides certifica- tion to programs that follow these principles, supports staff development, and encourages family involvement. There are currently over one hundred certified Nature Explore classrooms in the United States. COPYRIGHTED MATERIAL Why Garden?  •  9