You’ve never seen so much grass at a music fest as at Festival Palomino. No, not that kind of grass. Last year’s inaugural festival — co-curated by First Avenue and bluegrassy home-turf hosts Trampled by Turtles — was blessed with the kind of cushy green grass you can comfortably lay out on while soaking up all the sunshiny Americana, folk and roots music. Among the acts joining hosts Trampled by Turtles for the second annual Americana-breed music run on Sept. 19 are locally beloved indie-rock favorites Dr. Dog and Father John Misty, British folk hero Laura Marling, buzzing Southerners Benjamin Booker and Shakey Graves, rootsy critics' darlings Calexico and alt-country star Lydia Loveless.