Greenhouse growers are vowing to put up a fight over Ontario Premier Kathleen Wynne's plan to hike the minimum wage.

The operators say the province's proposal to increase the wage to $15 an hour will kill their businesses.

A higher minimum wage will only add to the financial constraints already being caused by Ontario's cap-and-trade tax and high electricity bills, said Gerry Mastronardi, who owns TG and G Mastronardi Produce in Leamington.

"The smaller producers are paying for all these costs that we have no control over," he told CBC News. "You can charge $20 for minimum wage. If there's no companies in Ontario, who is going to pay it?"

Jamie Diniro of Diniro Farms Inc. estimates his payroll will cost an extra $300,000 when the wage goes up to $15 per hour.

"I think the minimum wage hike will kill small business and small agriculture in the Leamington area and all over Ontario," said Diniro, who has 42 employees in his 16-acre operation on Mersea Road 5.

"We've got to make some noise," said Diniro. "We're going to try and rally. We're going to try and stop it."

He added the growers hope to invite Wynne down to Leamington to meet with them and other small businesses to hear their concerns.

"I'm not saying people can't make a decent wage, we will still give you a raise but a 30 per cent raise over a year and a half is just too much," Diniro said.

The operators say they can't raise the prices of the produce because they won't be able to compete with inexpensive Mexican imports.

Mastronardi says the only way he's been able to remain competitive is by increasing production through automation at his similar size operation.

Not all produce growers agree that a higher minimum wage will kill business. The local chapter president of the National Farmers Union says critics are "fear mongering."

"I honestly don't think that increasing the minimum wage for the limited amount of staff I have is going to hurt my business," said Mike Tremblay, who owns an organic farm near Tilbury.

He predicts the extra money in people's pockets will translate into increased sales of his produce.

One of his employees, Andrea Nickerson, says farm workers deserve more money. She worries, though, the cost of living could increase along with the wage hike.

"It's hard work, and we're out here every day in rain or shine working until our breaking point," she said.

The United Food and Commercial Workers support the increase. Officials say $15 an hour is a good start to put more money in the pockets of farm workers struggling to get by.

"In our work organizing and representing agriculture workers throughout the country, we have encountered countless workers, particularly in Ontario, who are struggling to survive on wages that barely put food on the table," the union wrote in a statement.

Meanwhile, Ontario Federation of Agriculture General Manager Neil Currie tells CBC News the wage hike may actually work against Premier and former Agriculture Minister Wynne's push, as part of the Local Food Act passed in 2013, to create 100,000 jobs in the agricultural industry.

He says greenhouse growers may have to add more mechanization to production.

"If we're producing the machinery then you're creating jobs. If we're importing the technology from offshore then we're losing jobs," said Currie.

He adds other farms may cut staff by producing crops which require less labour.