The article is based on agricultural customs and beliefs collected in the Lithuanian Folklore Archive taken from Lithuania by the ethnologist Jonas Balys and published in a book in the USA. The originals of the published sources are named in the Beliefs File (BF), and are stored in the library archive of the Institute of Lithuanian History. Based on this material, the article analyses the customs and beliefs of spring work in the Aukštadvaris region. The aim is to determine to what extent the published US sources correspond to the stored BF data, and it is concluded that most of the material published by Balys is BF, but there are unpublished as well as beliefs in the book which were not found in the Institute of Lithuanian History. The analysis of the beliefs about ploughing and sowing cereal crops and planting vegetables recorded in the Aukštadvaris region in the first half of the 20th century in the article revealed the possibility of using material from the book and the BF file to conduct a fully fledged study of the important local and wider area of ​​the economic and spiritual life of farmers in the first half of the 20th century.