The idea of eating local and organic food has gone mainstream in the United States. But in Hong Kong, where most food is imported and agriculture space is limited, the sustainable-food movement has struggled to gain momentum.

Of the 775 acres of land in Hong Kong that are devoted to agriculture, about 10% is organic, according to the Agriculture, Fisheries and Conservation Department (AFCD). The number of organic farms in Hong Kong rose to 331 from 10 in the past decade, but the output is still small: More than 97.6% of Hong...