A member of St Neots rural watch group alerted officers to the 90 growing in the village on Wednesday (September 4).
Officers seized the plants, some of which have grown to 9ft, and an investigation has begun to find the horticulturist responsible.
The plants are believed to have a potential yield of between £25,000 and £75,000.
St Neots neighbourhood Sergeant Adam Bagulay said: “Finding and seizing these plants has stopped a significant amount of illegal drugs getting to our streets.
“This is a great example of how important information from the public is in our ongoing effort to tackle illegal drug activity.”
Anyone with information about the plants or anyone who suspects illegal drug activity in their area should call police on 101 or report it online www.cambs.police.uk/rep.