Police have arrested a 27-year-old man after seizing 20 alleged cannabis plants and a hydroponics system.
Officers found the "matured" plants, worth an estimated £7,000, in the attic and an outbuilding of a house in Yate, South Gloucestershire.
The man was arrested during a raid on suspicion of cultivating the plants, and has since been released on bail pending forensic tests.
Police also seized money found in the house during the raid.
Sergeant Andy McIlrath said: "We will not tolerate drug production or dealing in South Gloucestershire.
"While cannabis has been downgraded from a class B to a class C drug, it is still an illegal. Anyone found in possession of it could still be arrested."