Urban farms are cropping up in metropolises across the U.S., with New York City proving to a be a particularly fruitful example. But this sustainable farming idea is more than an American trend, with cities worldwide taking strides in growing local produce and plants in developed urban areas. These efforts help to sustain the environment and educate citizens, potentially encouraging a cultural change on a global scale. No matter how much space you have or where you live, there is room for a little piece of green in the city. As well as the two examples we shared from New York City last week, these projects in Berlin and Hong Kong show that major international cities across the globe are taking urban farming to an impressive level:

Berlin - Prinzessinnengärten

In Berlin, a variety of old and rare crops are being grown on a renovated site in Kreuzberg. The 6,000-square-meter farm Prinzessinnengärten consumes the Moritzplatz space, which was once a vibrant shopping area and motorway junction. The once-damaged space is now an "agricultura urbana," a phrase symbolic of independent vegetable production and urban community. Prinzessinnengärten specializes in biodiversity, using recycled crates, rice bags and compost beds. The farm also avoids harmful pesticides and artificial fertilizers for growing its organic vegetables and locally produced herbs.

Prinzessinnengärten aims to raise awareness about problems associated with global-industrialized farming, seed-distribution monopolies and a global decline in biological diversity. By producing fresh and healthy food, the farm hopes to reduce CO2 emissions associated with farming, protect the local climate, and increase Berlin's biological diversity.

More than just an urban garden, Prinzessinnengärten fulfills the need for social learning and cultural change. Speaking to coolhunting.com, co-founder Marco Clausen says that he and his team strive to "make people living in the city aware of the food production system they depend on." Dedicated to hedonism and healthy lifestyles, the Prinzessinnengärten community strives to build a greener, more educated city.

Hong Kong - HK Farm

Hong Kong actively supports sustainability and local agriculture with its growing HK Farm. Founded in March 2012, the farm is managed by Michael Leung and a team of committed farmers, artists and designers. The farm is on the rooftop of an industrial building in Ngau Tau Kok, Kwun Tong, and its mission is to advocate the production of locally grown food.

Still in its infancy, the 4,000-square-foot farm grows various types of herbs and vegetables and harvests local honey. It's equipped with do-it-yourself growing containers and ecologically conscious installations such as a rainwater-collection system. From homegrown seedlings to a one-of-a-kind beehive, the the farm's projects are just the beginning of the urban-agricultural and sustainability movement in Hong Kong.

In the future, HK Farms plans to collaborate with other Hong Kong organizations, local communities and farmers with the aim of reducing carbon missions, conserving energy, and reducing dependence on imported food.

HK Farm will also offer various agricultural activities and tours, with workshops already taking place on site. The farm's blue print tote workshop leads participants through the ultra-violet-ray printing process to design custom tote bags using image blocking. The urban beekeeping workshop teaches participants about bees in Hong Kong and how to become an urban beekeeper. During the weekends, guests can visit the rooftop farm market to purchase seasonal produce. Companies are also welcome to privately tour the rooftop garden to learn more about urban-garden development and herb harvesting.

Images via Marco Clausen, wikimedia and HK Farm