It took just one day last week for Ontario Provincial Police to discover eight marijuana grow operations in cornfields and bush areas of Wellington County.

They located 1,280 plants, some as high as 2.7 metres tall, with a total estimated street value of about $1.3 million.

It's something Wellington officers do every summer, Constable Mark Cloes said.

But this year, the plants were bigger than they'd ever seen. "Some of the stalks were bigger than your arm," Cloes said.

He attributed that to the warm, wet summer -- ideal conditions for growing marijuana.

Pot growers are generally trespassers who wait until corn is about a foot high, then stomp it down and plant their own seedlings, Cloes said.

That makes it hard to track down who's responsible.

In the odd case they do find people hanging around the area and are able to charge them, Cloes said. But in this case, no charges were laid.

Farmers are generally aware this kind of thing can happen, he added, but it's still upsetting to them that their crop has been damaged and that someone has trespassed onto their property.

The plants were found in Guelph-Eramosa, Puslinch and Pilkington townships.

Cloes said officers are hoping to get the helicopter again so they can do checks in other parts of the county.