FOR a glimpse of agriculture in a land of high-rise apartment buildings, busloads of New York City schoolchildren have come for years to the Queens County Farm Museum. There they have petted Daisy the cow, walked through the cornfield maze, ridden the hay wagon and examined pens and fields that seemed just like those of a real farm.

But over the past year, the museum has become a real farm.

Since Michael Grady Robertson was hired as its director of agriculture a year ago, it has been raising more crops and animals, using sustainable methods, and plans to expand.

For the first time, the farm is running a stand at the Union Square Greenmarket. Every Monday since November, the farm has been selling greenhouse produce  more than 15 pounds of salad greens each week  eggs, honey, frozen heirloom tomatoes from last summer’s abundance, and pork from pasture-raised pigs.

Three blocks south of the Grand Central Parkway in Floral Park, the farm doesn’t have the pastoral beauty of Westchester County’s temple of sustainable agriculture, but it has a Queens-style terroir.