Vegetables are a recurring theme in Zappa's work.
- Plastic People (1966 - Los Angeles): "A prune is a vegetable ... no, a prune is not a vegetable. Cabbage is a vegetable ... makes it O.K."
- Call Any Vegetable
- Call Any Vegetable (1966 - Los Angeles)
- Invocation & Ritual Dance Of The Young Pumpkin
- Soft-Sell Conclusion
- Vegetables are used to spell out The Mothers' names on the cover of We're Only In It For The Money.
- The Story Of Uncle Meat: ""Certain sounds at certain intensities have amazing effects on plants & vegetables."
- One of the constellations on One Size Fits All is called Borscht, which is a vegetable soup.
- Another constellation is called Asparagus
- Yet another constellation is called Legume, which is the French word for "vegetable".
- When The Lie's So Big: "Ketchup is a vegetable" (a reference to a notorious wrong quote by Ronald Reagan)
- Champagne Lecture
- Panty Rap: "Bob Harris on keyboards, high vocal, trumpet and vegetables"
Zappa explains the meaning behind Call Any Vegetable in Absolutely Free: The Complete Libretto: "The best clue to this song might lie in the fact that people who are inactive in a society ... people who do not live up to their responsibilities are vegetables. I feel that these people, even if they are inactive, apathetic or unconcerned at this point, can be motivated toward a more useful sort of existence. I believe that if you call any vegetable it will respond to you."
On October 23, 1967, in New York, singer Nico sang with The Velvet Underground. Chris Darrow of the magazine "Kaleidoscope" recalled: "The opening night was very crowded and Zappa and members of the Mothers of Invention showed up to show their support. (...) Nico's delivery of her material was very flat, deadpan, and expressionless, and she played as though all of her songs were dirges. She seemed as though she was trying to resurrect the ennui and decadence of Weimar, pre-Hitler Germany. Her icy, Nordic image also added to the detachment of her delivery. (...) The audience was on her side, as she was in her element and the Warhol contingent was very prominent that night. However, what happened next is what sticks in my mind the most from that night. In between sets, Frank Zappa got up from his seat and walked up on the stage and sat behind the keyboard of Nico's B-3 organ. He proceeded to place his hands indiscriminately on the kebyboard in a total, atonal fashion and screamed at the top of his lungs, doing a caricature of Nico's set, the one he had just seen. The words to his impromptu song were the names of vegetables like broccolli, cabbage, asparagus... This "song" kept going for about a minute or so and then suddenly stopped. He walked off the stage and the show moved on. It was one of the greatest pieces of rock 'n roll theater that I have ever seen." 
- White Light/White Heat: The Velvet Underground Day by Day, Richie Unterberger, Jawbone Press, ISBN: 978-1-906002-22-0