After Leif's recovery, the couple bought a coffee farm known as La Colonia near El Tumbador. They managed it for several years, until 1929 when the plummet in coffee prices due to the Great Depression forced them to sell and buy a cinchona farm known as El Zapote, in the Escuintla Department on the slopes of the Volcán de Fuego. This turned out to be a precipitous purchase, as during World War II, the Japanese captured Indonesia, cutting off the supply to the seeds of the cinchona, which were needed to make quinine. The demand and Leif's agreement with the United States government and Merck and Company, soon made their farm one of the largest in the area producing chinchona.