“An apple a day keeps the doctor away” and “The apple doesn’t fall far from the tree” are proverbs that mean the same in English and Italian.  Perhaps because of the Italian passion for food, there are many other idiomatic expressions in Italian that are strange for Americans.  Here are some of them that use a fruit or a vegetable:

1. Essere come il prezzemolo (literally, to be like parsley) means to be everywhere, to pop up in all situations, just like parsley is used in many different dishes.  Example:  Giorgio è come il prezzemolo, lo trovi dappertutto = Giorgio (or George) is like parsley, you find him everywhere.
2. Non avere sale in zucca (literally, to not have salt in the pumpkin) means to not be very bright or have common sense. Zucca refers to the head and sale is a symbol of wisdom.  Example: Roberto è simpatico ma ha poco sale in zucca = Robert is nice but not particularly bright.
3. Essere una patata (literally, to be a potato) means to be clumsy or awkward.  Example: Che patata che sei = How clumsy you are!
4. La minestra riscaldata (literally, warmed up broth) is an expression that can refer to a romantic, platonic, or business relationship.  It means that when you try to revive an old relationship, it is never the same or it is the same old story.  Example: Ho incontrato il mio ex ieri, minestra riscaldata = I met my ex yesterday, it was the same old story.
5. Capitare a fagiolo (literally, to come along or happen like a bean) means perfect timing, at just the right moment.  Example: Brava, sei capitata a fagiolo, mi serve una mano = Well done, you’ve arrived just at the right time, I need a hand!  Variations are cadere /cascare a fagiolo = fall / drop like a bean and venire a fagiolo = arrive like a bean.
6. Cadere come una pera (literally, fall like a pear) refers to a person who suddenly falls asleep or to someone who falls easily into a trap.  Example: Ero così stanco dopo ho finito gli esercizi alla palestra che sono caduto come una pera = I was so tired after I finished the exercises at the gym that I dropped off to sleep (like a pear).  The expression is also used ironically to describe someone who suddenly falls madly in love.  Example: Raffaele è caduto come una pera per Luisa = Raffaele has fallen madly in love with Luisa. Variations include cadere come una pera matura = fall like a ripe pear, and cascarci /cadere come una pera cotta = fall like a cooked pear.
7. Valere un fico secco (literally, to be worth a dried fig) refers to someone or something that does not have value, or is not worth a damn.  Examples: Non vali un fico secco = you are worthless!  Hanno fatto le nozze con i fichi secchi = they spent nothing on the wedding.
8. Essere alla frutta (literally, to be at the fruit) means to hit rock bottom or to be at the end of the road.  Many Italian meals end with fruit, so the expression refers to reaching the end of something, usually a difficult situation with no way out.  Example: Hai sentito le notizie di politica oggi?  Siamo alla frutta = Have you heard the latest news in politics today?  We are at rock bottom!
9. Spremere come un limone (literally, to squeeze like a lemon) is similar to the English expression, to milk or bleed someone dry.  Example: L’ha sposata per i suoi soldi e poi l’ha spremuta come un limone = He married her for her money and then milked her dry.
10. Starci / entrarci come i cavoli a merenda (literally, to fit in like cabbages at snack time) means to have no relevance to the topic or the facts being discussed.  After all, who eats cabbage as a snack!  Example: Si può sapere di cosa stai parlando? Ci sta i cavoli a merenda con quello che dicevamo = What are you talking about?  It has no relevance with what we were saying.