NEW HAVEN - A once-vacant city block at the northern edge of Yale University now teems with exotic herbs and vegetables, tended carefully by a community of graying people from China who are here to look after grandchildren as their own children cultivate careers at the Ivy League school.

In the trellis-filled garden, a patchwork of small lots that are passed from family to family, they find friends, a routine for daily life in new surroundings and familiar vegetables that are fresher than anything they find in local markets.

"The sun is shining. I'm sweating. It's good," said 63-year-old Zhang Zaixian, of Beijing, who was watering chives one day as her grandson attended preschool. "I am happy."

The urban garden began taking shape a decade ago, a product of the expatriate community that has sprouted along with soaring numbers of students from China.

About a quarter of all international students at Yale come from China, which has become the biggest source country by far for international students in the United States. Yale had 680 international scholars, 516 graduate students and 58 undergraduates from China last year.

The gardeners come from a mix of urban and rural areas and abide by a few unwritten rules. Fertilizer is allowed, but pesticides are forbidden. Remove watering cans and clean up in the fall. Find another family to work your patch when you leave New Haven.

The garden succeeds, Zhang said, because the gardeners belong to an older generation that has patience.

All the plants are edible. They include varieties of beans, scallions, tomatoes and cilantro that they eat or use to season dumplings and other dishes.

The produce, grown from seeds found in New York City's Chinatown and some local Asian markets, is shared with other Chinese families that live in the complex of two-story apartment buildings across the street from the garden.

Yale owns the land, which had been overgrown before a few families started the planting, and Yale grounds crews have provided compost to help the gardeners. The only issues, they say, have been occasional theft or vandalism.