SUMMERLAND, British Columbia — Desperate to provide for his family, Hilario Mendoza leapt at the chance to leave Mexico to pick cherries on a farm in British Columbia.

But bad weather left him so idle that he often worked just three hours a day — far less than the 40 hours a week he said he had been promised under Canada’s program for temporary farmworkers. While he waited to go to the fields, he found himself crammed with 34 other laborers into a small house where rain leaked onto their beds.

Months of complaints went nowhere — and then he was abruptly sent back to Mexico.

“We were abandoned,” Mr. Mendoza said of his 2014 experience on the farm. “There are lots more people in Mexico wanting to work in Canada, so they don’t protect our rights.”

Canada’s seasonal agriculture worker program was set up to recruit migrants from Mexico and 11 Caribbean nations to work for up to eight months a year to address chronic labor shortages.