As many as 500 massive marijuana plants have been found growing in a two corn fields near Markham, police said Thursday.

Police made the find in the middle of the fields Wednesday, during a patrol by officers who were riding ATVs and were accompanied by a York Regional Police helicopter.

“The helicopter spotted what appeared to be something that wasn’t corn in the corn field and worked with some of the officers that were on the ground to direct them into where those plants were located,” York Regional Police Const. Andy Pattenden told CTV Toronto.

The helicopter flying overhead found many more plants in a second field.

“Those officers were able to determine that it wasn’t corn, but it was two, quite large, outdoor marijuana grow operations,” said Pattenden.

Each plant is nearly two-metres tall.

The street value of the drugs is thought to be $1,000 per plant, for a total street value of up to $500,000.

The size of the plants indicates that they have been there for some time, Pattenden said.

Police pulled the plants from the ground and they will be taken for analysis before being destroyed.

Pattenden said police are working with drug investigators to find suspects.

With files from CTV Toronto’s Colin D’Mello