A 33-year-old from Cospicua was arrested after police raided houses belonging to him in Xaghjra and Cospicua.
A police statement confirmed that six plants had been found in Cospicua and a further three in the other house.
They also found a container full of dry cannabis leaves.
Duty magistrate Joe Cassar was informed and appointed various experts to assist in an on-site inquiry.
In six days, police have seized more than 300 cannabis plants. Police inspectors Norbert Ciappara and Pierre Grech are investigating.
The 33-year-old is expected to be charged in court in the coming days.