With his national nonprofit Big Green, social entrepreneur Kimbal Musk is on a mission to bring healthier food to millions of underserved American schoolchildren. With obesity rates among kindergartners topping 20% in some states, causing a public health problem on par with gun violence and smoking, Big Green builds school gardens in low-income districts where over 60% of pupils qualify for free or reduced lunch. The goal is to teach “food literacy” as early as possible, letting students grow fresh fruits and vegetables in an outdoor classroom environment. Big Green’s high school–level participants can sell their fresh produce at local farmers’ markets and keep the profits. The organization’s programs are running in over 400 schools, with 30 more in the pipeline, reaching more than a quarter million schoolchildren to date. Musk’s goal is scale: Big Green has plans to expand to troubled areas in 10 major U.S. cities, reaching 1 million students, by 2020.