While at the library he continued his self-education through evening classes, learning Swedish, and travelling widely. Stearn used his three-week annual leaves in the pre-war years to visit other European botanical libraries, botanic gardens, museums, herbaria and collections, as well as collecting plants, with special emphasis on Epimedium and Allium.[2] His travels took him to Switzerland, Italy, Germany, Austria, Czechoslovakia, Denmark, and Sweden.[39]