We Can't Eat America's No. 1 Crop We grow three times more grass than even corn By Michael Harthorne, Newser Staff Posted Aug 20, 2015 1:00 PM CDT 60 comments Comments New research shows lawns are America's largest crop, beating out even corn. So, what's that mean for the environment? (AP Photo/Rich Pedroncelli) (Newser) – Corn might be the United States' No. 1 food crop, but it doesn't hold a candle to the amount of grass being grown by accidental farmers around the country. In a look at America's "most useless crop," io9 surfaces decade-old research from NASA's Earth Observatory that may not be the most current but is pretty fascinating. Christina Milesi started researching lawns in 2003, spurred on by a business class proposal she drafted while working on her PhD at the University of Montana: How much water could be saved by using weather forecasts to let homeowners know when and how much to water their grass? Earth Observatory reports. To do that, she needed to find out how much of the United States was covered by lawns, something no one else had ever done. So she submitted a proposal to the NASA Earth System Science Fellowship and got started. The modest size of most lawns and vast number of them meant using satellites was out. So Milesi used a combination of aerial photographs, known paved surface areas, and her own mathematical formula to figure it out. Her "conservative" estimate: nearly 50,000 square miles of lawn in the US, which in turn is three times more than corn. She also found it would take approximately 200 gallons of fresh water per person per day to keep America's lawns well-maintained. That maintenance is a factor in how lawns became popularized to begin with. io9 traces the history of the lawn from the first lawn-care manual (written in the 1200s) to present day, noting that the very wealthy began to adopt them in the 1600s. But keeping things manicured required a slew of scythe-armed servants. The invention of the lawnmower in 1830 began to make lawns much more attainable. io9 has more.