The founder of BK Farmyards advocates using urban land to grow crops closer to home.Growing food in dense cities like New York might seem like an oxymoron, but why shouldn't we grow food right next to our plates to reduce the waste? Today, most Americans live in urban areas. And as the population densities have shifted around the country, we should re-examine backyards. They can be more than places to relax; they can be places to grow vegetables.There are more than 10,000 acres of unused land in New York City, according to the Department of Planning, and 1,500 of those acres are in Brooklyn. On top of that, there are countless privately owned sunny backyards. Farming 36 backyards in Crown Heights or Bay Ridge is the equivalent to farming an acre. In other words, Brooklyn is ripe for decentralized urban farming.My organization, BK Farmyards, is an attempt to do that by pairing yard-owners with urban farmers, where social media plays a vital role in connecting landowners with gardeners. Using our website to crowdsource available land, BK Farmyards found 700 square feet in backyards in Ditmas Park. We had a six-person CSA for 12 weeks. We're are excited for our expansion next year: A one-acre youth farm with the High School for Public Service.We're not alone. Sharing Backyards is a combination of online dating and Google maps, which allows you to meet your land match as a farmer. Hyperlocavore meets a similar need: sharing local resources through a social network interface. In the U.K., a similar effort called Land Share has 43,900 users. While these projects have shown us a glimpse of the possibilities, there is still enormous social media potential untapped for farmers.At BK Farmyards, our hope is to inspire the future planning of cities to include urban agriculture. We can change urban policy through social movements, and what better way to show support than through familiar channels such as social media. At this year's Pop!Tech conference, Nick Felton said that 68 percent of user-generated online conversations were about food. What if we could harness that energy to not only produce more food in urban centers but to change urban policy and ensure the future of urban agriculture?Guest blogger Stacey Murphy runs BK Farmyards. She's hoping you will sponsor her one-acre youth farm on Kickstarter.