Aaaaaaaargh! Lost it again! Grrrr!

The last singer I recorded about 10 years ago had songs from his farming community, songs he had learnt at school and songs he had written about his own life in farming. To me they were all folk songs.

No modern scholar has tried to put a time limit on when a song becomes folk. Obviously the longer a song remains in a folk community the more of the characteristics it picks up, but at what point a song becomes folk has not been established. IMO it doesn't need to be.