The Supreme Court of Canada has ruled that a provincial ban on farm unions is constitutional, denying more than 80,000 Ontario farm workers the right to unionize.

"Quite frankly, we are shocked," Mindy Leng, a former Ontario farm worker, told CBC News.

"This decision is not really worth the paper it's printed on," said Stan Raper of United Food and Commercial Workers Canada. "It's not even fertilizer."

Some producers, however, were encouraged by the ruling, saying the ban prevents higher labour costs.

"It would deter the industry or slow the industry down — stop new processors from coming in the area," said Corey Versnel, who runs a vegetable farm in Kingsville, Ont.

One farm worker told CBC she does not personally feel the need for a union, but was sympathetic to other workers who do.

"If they have everything they need and if they don't really want a union that's great. But for the workers who feel that they are in a poor setting — like if they feel they are being discriminated against or if they have bad working conditions — I feel bad for them," said Angela McHardy.

In November 2008, the Ontario Court of Appeal upheld a charter challenge brought by the United Food and Commercial Workers Canada union that the ban was unconstitutional.

The decision pointed to freedom of association rights to organize for the purposes of collective bargaining.

The Ontario government appealed the ruling to the top court, which heard arguments in December 2009 and ruled Friday, handing down an 8-1 decision upholding the law.

The eight justices who allowed the appeal were divided on exactly how the workers should be allowed to bargain, but ultimately ruled that the existing act is sufficient.

Ontario's agriculture minister said she supports the decision but is willing to listen to the concerns of workers.

"It's a very careful decision," Carol Mitchell said Friday.

"The Supreme Court has reaffirmed that the Agriculture Employees Protection Act is appropriate," she said.

"We are always listening and willing to work with the agricultural community," she added.