It is 20th century, March 1954, had a related phrase, in a glossary of jet pilots'
slang:"Bought a plot, had a fatal crash."That clearly refers to a burial plot.'bought' is, being killed. It's from Cyril Ward-Jackson's It's a piece of cake; or, R.A.F. slang made easy:"He's bought it, he is dead - that is, he has paid with his life."
Specific references to 'the farm' come a little. Here's a citation from 1963, in Ed Miller's Exile to the Stars:"The police dispatcher says a plane just bought the farm.