STRAWTOWN, Ind. -- It is prime growing season in Indiana, but it's not just produce that's popping up in farmers' fields.

Thursday, the Indiana State Police scoured rural farmland by air and on the ground, looking for marijuana plants, 6News' Jack Rinehart reported.

"They were beginning to bud. This is the time of year for that. When they come back here in a month, they're going to be very upset," said trooper Rob McKeemon, part of ISP's Marijuana Eradication Unit.

Growers who hide their plants in farm fields go to extreme lengths to disguise their crop, troopers said, but in many cases, what the plants need the most end up giving it away.

"There are different ways they can camouflage their marijuana plants, but in the end, it's got to have sunlight," McKeemon said.

Troopers recovered several plants from a Hancock County cornfield Thursday, as well as 50 from a field in southeast Madison County.

"It's hard to imagine that there could be somebody in the area that would take advantage of someone else's property for that kind of business. It's kind of scary," said Kim Gustin, who lives near an area where troopers discovered pot plants.

So far this year, the state police have seized more than 21,000 plants. Officials said they dedicate three days a week to seeking out marijuana operations.

The ISP has a hot line to call if someone suspects an indoor or outdoor marijuana grow. That number is 888-873-1694. Callers can remain anonymous.