A 4,000sqft rooftop in the industrial neighbourhood of Ngau Tau Kok is home to HK Farm, which grows organic produce and promotes the consumption of local fruits and vegetables.

When it comes to greenery in Hong Kong, looks can be deceiving. The city is chock-a-block with commercial skyscrapers and high-rise tenement-style residences -- with barely enough room for its population of seven million, let alone swathes of grassy farmland for crops.

But in actuality, less than 25% of Hong Kong's land is developed and 40% of the total space is made up of parks and nature reserves. And though much agricultural production has been outsourced to southern China, there remains a motley crew of modern-day farmers -- made up of both veteran old-timers and a young, trendy trowel-toting set -- who are committed to promoting the consumption of locally-farmed fruit and vegetables and growing produce in even the most urban areas of Hong Kong.

Michael Leung, a designer with a self-taught passion for urban beekeeping,  is among the young and trendy group. Along with compatriots Matthew Edmondson and Glenn Ellingsen, Leung founded HK Farm in April 2012, where the team grows organic herbs and vegetables in an unlikely setting -- a 4,000sqft rooftop in the grey, industrial neighbourhood of Ngau Tau Kok. In its first months, HK Farm successfully cultivated tomatoes, basil and other crops, opening up their rooftop to visitors on Saturday and Sunday afternoons.

"We're interested in people seeing the rooftop,” said Leung. “If they want to buy herbs, we can cut them right in front of them. Things seem to grow in our urban environment."

Though they took a short break during the summer when Hong Kong's climate is too hot for many plants, in September HK Farm will be doubling the number of crops they grow from 10 to 20, from string beans and papaya to jalapeno peppers and okra. They’ll also be starting up their weekend open houses again. It's a real community effort, using soil from a local farm in their planters and taking waste from nearby restaurants to make fertilizer and future plans include collaborating with local cafes. Their work has been recognized internationally, too; HK Farm was asked to represent Hong Kong at the Venice Architecture Biennale this year.

Leung notes the myriad benefits of rooftop farms, from helping to improve air quality to reducing air-conditioning and heating costs in the building below. Along with Kubrick, an indie cafe, bookstore and small publishing house in the Yau Ma Tei neighbourhood, HK Farm is producing a book about urban agriculture in Hong Kong.

"It will be a tool to help convince landlords, property developers and the government to really start thinking about urban agricultural projects," Leung explained.

Hong Kong is also home to other rooftop farms, such as City Farm and Eco-Mama. Like HK, they welcome visitors to show that, as unintuitive as it may be, Hong Kong is a concrete jungle that has elements of a green one, too.

Hana R Alberts is the Hong Kong Localite for BBC Travel