Don't know beans

Does anyone know this phrase's origin and meaning?

"John doesn't know beans about neoclassical architecture" means that John knows little or nothing about it. Beans are common and cheap, so that a quantity of beans illustrates the idea "almost nothing." Similar phrases exist, such as "doesn't know diddly-squat."

"Hill (row) of beans, a": Defined in the Dict. of American Slang as "Of little significance, importance, or benefit; insignificant, inconsequential."