The world’s population just keeps getting bigger. A few weeks ago we hit 7 billion. By 2050 more than 9 billion will call the Earth home, and an estimated 80% of us will live in cities with food access problems. Add to that the fact that we could eventually run out of productive soil and water — not to mention the whole other host of problems associated with modern agriculture such as deforestation, chemical-laden fertilizers and carbon-emitting transportation — and it’s easy to see why roof-top farms are cropping up in urban areas nationwide. Though full-fledged vertical farms, called “farmscrapers,” exist only in theory and experiments today, with the increasing urban population, the need for those who specialize in locally grown, sustainable food will only increase.