A term loosely used by police and those who know nothing about growing or smoking marijuana. In reality, a "grow op" should be a large scale commercial operation with 100's or 1000's of plants, but most are small suburban homes with just a few plants for personal and friendly use. These small indoor gardens attract the attention of police usually after a "rat" has been interrogated. Sadly in Canada, owners of small personal indoor gardens are often charged with having a "grow op" and "production of a controlled substance for the purpose of trafficking"... even though they got caught with say 10-20 plants and a few ounces of dried bud. It is a sad state of affairs. Prohibition has many victims, but police and courts benefit greatly.
Detective: "It was a grow op, so we are charging you with production for the purpose."
Accused: "But it was only 10 plants and a quarter pound of bud!"