It has a single tubular leaf and up to forty five green to yellowish-green flowers with a white labellum.

A similar leek orchid occurring in Victoria, previously included in this species, is known recognised as the undescribed Prasophyllum sp.

[5] Prasophyllum validum was first formally described in 1927 by Richard Sanders Rogers and the description was published in Transactions, proceedings and report, Royal Society of South Australia.

[1][6] The specific epithet (validum) is a Latin word meaning "strong" or "sound".

The main threats to the population are competition from weeds, grazing by kangaroos, rabbits and livestock and by vehicles and machine use near roadsides.