Is "ghost month" really a Buddhist concept? I currently live in Taiwan, and we are currently experiencing "ghost month". The Wikipedia article for Ghost Festival starts with:


  The Ghost Festival, also known as the Hungry Ghost Festival, Zhongyuan Festival or Yulan Festival (traditional Chinese: 盂蘭節) is a traditional Buddhist and Taoist festival held in Asian countries.


The use of "traditional festival" suggests it may be more of a cultural tradition than a strict Buddhist concept.

Does the idea that hungry ghosts or spirits escape from (some subset of) Hell once a year and need to be fed have any root in the early origins of Buddhism, or is this an add-on concept coming from cultural ideas or perhaps from Taoism?
It appears this practice originated from Taoism, not from Buddhism. However, there is an account of hungry ghosts stories in Buddhism. (Petavattu)
In Sri Lanka, we pass merits to departed relatives but there is no specific date for it.