What is the origin of the idiom "small potatoes" and when to use it?

The idiom "small potatoes" originated in the United States during the 19th century and was associated with the idea of small, insignificant, or unimportant things. Potatoes were once considered a humble and inexpensive food, so this expression is used to suggest that something is of little value or consequence, like a meager or trivial portion of a meal.