从钢筋水泥到绿色天堂

Hong Kong is a shoppers' paradise, but there’s one thing residents find difficult to buy --- locally grown fresh food. Densely-populated Hong Kong has a lack of farm land, but the demand for local organic food is on the up. So why not create more agricultural land by building upwards? A band of innovative city dwellers are doing exactly that -- growing vegetables and plants on rooftops or skyscraper walls.

7 million people. 8,000 skyscrapers. One of the planet’s most densely populated cities crammed onto a few tiny islands. Agriculture almost does not exist in Hong Kong, with only a little over a percentage of land used for farming. But some are trying to find alternative spaces to grow food.

This is a vegetable garden that seems no different from any other. But, it’s in an unlikely place on the rooftop of a 14-storey building in eastern Hong Kong. Looking down from above, the patch of green stands out in the concrete jungle."

It’s a patch of hope that agriculture can thrive even in one of the world's most congested cities. Osbert Lam started operating this farm five years ago.

He is the first man in the city to grow food on the rooftop of skyscrapers. The farm, less than a quarter of a football court in size, has 500 planter boxes.

Each box is for rent at 20 US dollars a month, and is capable of producing 14 kilograms of vegetables a year. Osbert now has three vertical farms in different locations, helping city gardeners enjoy fresh and organic produce. He says market demand is huge.

“If you look from the Google map, city like Hong Kong is very congested. But you can still see a lot of rooftop left unused. So by making use of these rooftops, which have good sunshine, good air flows, and turn them into vegetable production, it could be a way to solve the food supply, even though a minimal percentage in the food supply chain. It’s a very valuable, low-carbon vegetable production,” Osbert said.

The space-starved city produces only 2% of its own food. The rest largely needs to be trucked in from the Chinese mainland. So more and more people, who demand local organic food, are looking skyward.

“The all year round weather is good for growing vegetables. Unlike Tokyo and New York’s cold weather in winter, Hong Kong has good weather that we can grow vegetables all year round. The soil is specially prepared for the climate here. There are occasionally serious rainfalls in Hong Kong. The soil needs to have very good drainage, in order to make it suitable for crops,” Osbert said.

Dickson Despommier, an ecologist at Columbia University, introduced the concept of vertical farming in 1999. It creates a world where every town can have their own food source, and where an elevator ride can transport people to nature's grocery store.

It’s not just about feeding people but also protecting the environment.

“The sky woodland has high attraction for both people and wildlife, thus enhance urban biodiversity in our city. With woodland and vegetation on the rooftop, we can also cool the city very effectively. And for those living on the top level, you have green roof above you , you will have much cooler indoor space. You will use much less air conditioning reduce the effect of climate change,” said Prof. C. Y. Jim, the University of HK.

So experts say vertical greening is a good way to green Hong Kong. Gardens on the roofs gardens on the walls.

Located in an old industrial area, this green building brings vitality to the dense blocks. Its designers say the target is to create some casual green space for its users and the nearby neighborhood.

“The vertical wall or roof garden have three benefits for us. First, it’s very nice, very green, like a green building. Second, it’s good to the environment. The vertical wall and roof garden can reduce the heat island effect, a major problem we want to tackle in the urban context. Third, it can also help the air flow,” said Benny K. M. Chow, director of Sustainability, AEDAS.

Architects say vertical greening is growing trend, and they are working towards that direction.

Taking the concept further, one Spanish architect even proposed building 185-meter farm towers in one Hong Kong district.

Made of lightweight recycled materials, the towers would grow food from liquid nutrients instead of soil…
on a series of rotating floor-plates that would give crops the maximum amount of sunlight.

The idea drew mixed reactions from residents.

"It could be a new landmark, attracting more tourists and money."

"The idea is good. It occupies less land, and develops upwards. It’s a sustainable method of development."

"It’s nice in Hong Kong with our huge population and lack of land. But the cost could be very high."

"I don’t like it. It looks weird. Hong Kong has no enough places to live, how can we use one tower to grow vegetables?"

“They look very nice on paper, but I’m wary of the sustainability of such endeavors. First, it’s very expensive to build. Secondly, it’s not easy to maintain. Thirdly, you have to find right technology and materials,” said Prof. C. Y. Jim.

As there are still challenges to make such fantasy buildings come to life, it’s more practical to green the existing buildings.

Imagine a city where food can be produced where it’s consumed… where skyscrapers are filled with flowers, fruits and vegetables.

Like Osbert, people hope that one day, the patch of green in the concrete jungle can be expanded to a green paradise.