Zenger Farm has at long last retired the two-bedroom farmhouse where it operated its community farm and welcomed 10,000 school children every year. The Portland nonprofit cut the ribbon on its 6,600-square-foot urban grange last week and is already welcoming children, community groups and campers. Take a tour of Zenger Farm and its new urban grange in the photo gallery above. Established in 1999, Zenger Farms is a 20-acre working farm and educational center at Southeast 117th and Foster Road in…