Ontario Provincial Police said they have finished destroying the 40,000 marijuana plants found growing in a cornfield near Pembroke, Ont.Ontario Provincial Police said they have finished destroying the 40,000 marijuana plants found growing in a cornfield near Pembroke, Ont. (Ontario Provincial Police)

People living near an eastern Ontario marijuana grow operation billed as Canada's largest ever had no idea there was such a crop amid the corn.

"We didn't know anything until the police came here," said Clarence Romhild, who lives across the street from the farm where an estimated 40,000 marijuana plants had been flourishing.

"We didn't know anything until helicopters came over, and then we assumed something was going on."

On Tuesday, Ontario Provincial Police said they had finished destroying an estimated $40 million worth of plants from the 43-hectare farm they raided last Thursday on B Line Road in Laurentian Valley Township near Pembroke, Ont., about 150 kilometres west of Ottawa. OPP said they believe it's the largest grow operation found in Canadian history.

Romhild said the farm had been bought about three years ago by some people who didn't live there but came and went.

"They kept pretty quiet," he said.

Owners didn't harvest their corn

John Mau, who lived in the neighbourhood for 30 years, said he didn't think anybody knew the farm's owners.

He said a farmer who lived nearby remarked that it was strange that people would plant corn and not harvest it, but he himself never thought too much about it.

Romhild said police watched the farm from his driveway for two or three days before executing their search warrant.

Det.-Sgt. Dave Howat said police received a tip about the crop, which was just beginning to be harvested.

As of Tuesday, police still had not made any arrests in the case. Howat defended the OPP decision to raid the farm while no one was there.

"It was taken down in a timely fashion as we saw fit," he said. "Suffice ... to say the timing was what we decided on for officer safety and such."

He added that the investigation is still in its early stages.

In addition to the massive crop of marijuana, police also seized two tractors, a combine and other farming equipment from the site.