A dog walker called police after finding several cannabis plants dumped by the roadside.
The man came across the mature plants and some foil while out walking on Sunday on the old A509 Wollaston Road in Bozeat.
A police spokesman said: “We had a report that a load of cannabis plants and foil had been dumped in a layby on the A509 by Fullwell Road, Bozeat.
“It was six to seven mature cannabis plants and some foil.
“A man saw them when he was out walking his dog.
“We have been out and it has been collected and removed.”
The spokesman said they would like anyone who has any information about the plants or who saw anyone acting suspiciously in the area to call them on 101.