In this piece, FCRN member Mike Hamm critically considers the environmental sustainability of vertical- and indoor farming. In particular, he explores and challenges claims that fully indoor production systems can provide a significant source of food for urban areas at low carbon cost.  Ultimately, he argues that there are a number of other urban and peri-urban food growing options that offer greater potential, and deserve more policy attention and support.Michael W. Hamm is a C.S. Mott Professor of Sustainable Agriculture at Michigan State University and Director of the MSU Center for Regional Food Systems. Mike is also a Visiting Fellow of Mansfield College and the Environmental Change Institute, University of Oxford, and an FCRN network member.