Selma Nielsen’s father Jens A. Nielsen was a sailor, she passed on about one hundred and fifty folk-songs, a large number of which were seafaring songs that she had learned from her father. She collected and noted the texts and melodies herself and in 1921 came into contact with Dansk Folkemindesamling (the Danish Folklore Archives), specifically with Hakon Grüner-Nielsen.
She owned a number of the printed songs issued by Julius Strandberg’s broadsheet ballad workshop, but learned most of the songs by hearing them being sung.