Specifically, an illegal basement operation for growing large quantities of hydroponic pot to sell on the street, often backed by the Vietnamese mafia or Hell's Angels.

Alleged by most Vancouver newspapers to be firetraps because of their extensive lighting and humidity requirements, and their penchant for illegal electrical connections.

Spin-off phrase: "grow-rip", where a different (heavily armed?) criminal gang will break into the grow-op and seize all the pot they can grab from the original criminals.