By Marianne Bray
HONG KONG - At the top of a three-storey building in Hong Kong, with car horns blasting on the streets below, Jim Fung teaches a dozen students how to thin out choi sum vegetables.
"Always use the resources you have," the instructor said as he placed shredded office paper into soil-filled plastic crates and wound string around bamboo sticks to make support frames.
Fung was coaching the first cohort of students in an academy run by social enterprise Rooftop Republic to teach a new generation of urban farmers as demand for their skills soars.
The organisation is spearheading a movement to turn Hong Kong's idle rooftops and urban spaces into farms to help residents reconnect with nature and make the finance hub more liveable.
Once a cluster of fishing and farming villages, Hong Kong is now one of the most densely packed cities on Earth, with 7.4 million people living on a quarter of its 1,100 square km (425 square miles) of land.
The rest is mainly country parks and rural areas, but living in skyscrapers and working long hours has caused Hong Kongers to lose touch with the nature around them, say students at the academy.
"We've become detached from the history of the sea and land that Hong Kong had," said Jessica Cheng, a Rooftop Republic student who works for a philanthropic organisation.
Andrew Tsui, one of Rooftop Republic's three co-founders, said he wants the academy to be "Le Cordon Bleu" (a famous cookery school) of urban farming.
To him, that means a place where graduates become masters of the practice and at the same time become "stewards of our planet, our wellbeing, and our communities", he said.
Founded in 2015, Rooftop Republic has set up more than 50 urban farms so far.
It launched its academy in March, starting with events and workshops. The organisation's first urban farming course, which began last month, teaches students botany, organic farming and how to manage soil, pests, weeds and water resources.
Their classroom sits atop the headquarters of Hong Kong's Business Environment Council, a non-profit promoting sustainability in the world's second most-expensive city for property after Monaco, according to global realtor Knight Frank.
Since 2008 more than 60 rooftop farms have sprouted up around Hong Kong, covering 15,000 square metres (161,460 square feet), said Mathew Pryor, who heads the University of Hong Kong's landscape architecture division.
He estimates another six square km (2.3 square miles) of rooftop space could be available - about half the size of Hong Kong's airport and just less than the seven square km (2.7 square miles) of agricultural land in the city.
Hoping to expand that potential, Tsui told the Thomson Reuters Foundation that Rooftop Republic has been working with developers to include rooftop farms in their design blueprints.
One day, he predicted, rooftop farmers will be as necessary as facility managers who look after clubhouses and pools.
His organisation will train about 150 urban farmers over the next year, he added.
"We have the power to shape the future city we live in ... through demonstrating how adopting an urban farm lifestyle helps the end consumer become aware of ecology, biodiversity, nature, wellbeing and a circular food system," Tsui said.
In the 1,200-square-metre (13,000-square-foot) Sky Garden in Metroplaza Mall - the largest urban farm atop a retail mall in Hong Kong - residents can cultivate edible flowers and fruit trees as they attend lifestyle classes like mindful gardening.
Research by ecological and agricultural experts shows rooftop farms not only produce food, but also create green spaces and boost biodiversity.
They also help mitigate the so-called "heat island" effect in cities, when heat is trapped by dark-coloured roads and buildings.
Just as importantly, Tsui said, the farms build communities among the people who care for the crops.
"There is huge potential for rooftop farming in a high-density city," said Pryor, the landscape architecture expert.
"Particularly if it can be aligned with social issues, like aging-in-place," he added, referring to when people have the chance to grow old in their own homes.
Access to a nearby rooftop farm can help the elderly engage with their community and keep them in good mental and physical health, he explained.
In a study of 108 people using rooftop farms, Pryor found more than three-quarters of respondents said they saw social value as the most important benefit of working on the farms, with socialising topping the list.
They added it was good for their health and for learning about nature.
Such learning is key, said academy student Alyson Hamilton, a teacher who runs her school's micro-garden.
"(My) students have no knowledge about food, where it comes from, how much plastic it comes in," she lamented.
NATURE AND COMMUNITY
Alongside the high cost and scarcity of space in Hong Kong, the main challenge for budding urban farmers is having the right conditions, Tsui said.
The basics that plants need - natural sunlight, fresh water and fresh air - are often in short supply in the city, he added.
"Our big question is, if many of our city spaces are not suitable for plants to survive, then how are they conducive for human beings?" he asked.
With more than half the world's population living in cities, Tsui said he's using what he has learnt from rooftop farming to engage urban planners and shape a human-centric city.
He questions whether the move toward so-called "smart cities" around the world actually allows city-goers to live smarter.
"Are we smarter in getting closer to nature for our wellbeing? Are we smarter in the way we design our neighbourhoods, allowing access to fresh air, direct sunlight and nature?" he asked.
Working with architects, planners and developers allows Rooftop Republic to incorporate some of those factors into the blueprints for new developments.
But rooftop farms - which are legal in Hong Kong - currently exist in a grey area between formal city planning and informal community action, said Pryor, the landscape architecture professor.
Both the city's New Agricultural Policy paper, published in 2014, and the Hong Kong 2030+ strategic plan acknowledged rooftop farms as playing a significant part in urban agriculture. Government officials did not respond to interview requests.
Pryor would like to see the city's government include such farms into mainstream building and land policy, in recognition of how important they are for creating sustainable cities.
Tsui agreed, saying urban planners need to create ecosystems to nurture people's connection to nature.
"We want to put nature and community back into where we play, where we work, where we live," he said.