In e-mail on 9/24 from Masayoshi Yamada, Emeritus Professor of Linguistics, Shimane University (author of, inter alia: A Dictionary of Trade Names and A Dictionary of English Taboo and Euphemism), substantially edited:
Recently, I happened to read the newspaper comic strip Zits; on September 23 and 24, the main character Jeremy uses the expression “I had the radish”. One of the few dictionaries which defines it:
have had the radish ‘to be no longer functional or useful; to be dead or about to perish’. Local to the state of Vermont. Primarily heard in US. (Farlex Dictionary of Idioms, 2024) (Free Dictionary link)
However, I don’t have any clue to its etymology: why radish? And is it so local to Vermont? I have no idea which language source the Farlex Dictionary is based on. [AZ: It cites the Free Dictionary, which aggregates information from many sources, so that’s not especially helpful.]
I pointed out to MY that in the strip, Jeremy decides to just invent (make up) some expression, to see if he can get it accepted. And picks had the radish. Presumably in the belief that no one had ever used it as an idiom. The first three strips (in strips to come, Jeremy eventually concedes that his idiom has had the radish):





