These city kids from Boston may not look like conventional farmers, but they’re spending part of their summer getting their hands dirty. They’re learning how to build solar-powered hydroponic systems that grow organic vegetables without soil. With support from the National Science Foundation, Boston College educator Mike Barnett and his team developed the Urban Hydrofarmers Project to engage students in math and science through hydroponic farming and green energy technology. And, because the teens sell what they grow at farmers’ markets, the students get to experience green entrepreneurship. Barnett and his team have also partnered with the STEM Garden Institute to bring hydroponic farming into classrooms throughout the U.S. Part of the National Science Foundation Series “Science Nation.”