Rooftop Farming


Urban farming on rooftops has been gaining traction in cities around the world. Its rise can originally be traced to consumers increasing awareness of carbon emissions that result when our food travels hundreds, if not thousands of miles from the farm to our table. As an experienced urban farmer that grows on the rooftops of commercial buildings such as the Bank of America Tower, and as a farming instructor at schools and universities such as HKU, I’ve gained an in depth understanding of the challenges, as well as the opportunities.

Space limitations in a city such as Hong Kong make rooftop farming an attractive option for growers. Farming on the rooftop creates numerous social, economic and environmental benefits. A HKU paper examining green roofs concluded that:

“Apart from enhancing the city landscape and environment, mitigating the urban heat island effect and improving air quality, green roof can improve the microlimate and increase the life span of waterproof and insulation facilities on the roof. Consequently, roof greening with a sufficient large scale is conducive to energy conservation and life cycle cost saving for the urban city.

Green roofs can help reduce three of the four top problems facing the society in the next 50 years: energy, water, and environment. In this way, the green roof technology has a potential to improve quality of population health and welfare in the urban areas with dramatically reduced vegetation.”

Rooftop farms reduce the carbon footprint of our food. Most of our fresh vegetables are transported hundreds of miles in refrigerated trucks. For consumers, rooftop farming provides fresher, more nutritious produce and reduces our reliance on imports which today account for 98% of all vegetables consumed in Hong Kong. Vegetables grown on rooftop farms can reach consumers in a day instead of weeks. According to this Harvard paper, “foods grown far away that spend significant time on the road, and therefore have more time to lose nutrients before reaching the marketplace.” Up to 40% of the nutritional value of fresh produce can be lost during transport and distribution.

Urban farming can also help to address the issue of our ever expanding landfills. Food waste constitutes 37% of total landfill waste. This food waste can instead be composted to produce a nutrient rich growing medium which is highly sought after by organic growers. In Hong Kong, most food waste is not used to make compost in part because there is no local demand for the end product. Urban farms create local demand for compost, thereby helping to reduce the amount of food waste entering our landfills.

Increasing demand for food waste compost has many positive effects. First, it recycles the nutrients contained in our waste to grow more fresh produce. Second, as a superior growing medium it reduces demand for fertilisers. Third, it reduces greenhouse gas emissions. Dumping food waste into an anaerobic environment, such as a landfill, produces methane, a greenhouse gas at least 16 times more powerful than CO2. Aerobic composting of food waste can reduce the climate change impact of our landfills.

Rooftop farming also creates the opportunities for employment, education and community engagement. For example, the Riverpark Cafe in NYC employs a full-time professional farmer to create a unique farm-to-table dining experience. In Detroit and Vancouver, urban farming projects have revitalised communities and created employment. At Wildroots Organic in Hong Kong, we have been integrating the science curriculum in hands on farming lessons that engage students.

While urban farming can help address many of our social and environmental issues, there remain many challenges that make widespread implementation difficult. In a future article, we will explore these challenges and share our lessons learned.


Is the Science Museum Out to Sea?

“….A large centrepiece comprising plastic flotsam collected from the beach cleaning operations in the North Sea, Hawaii, the Baltic Sea and the rest of the world is displayed with the aim of arousing public awareness of plastic waste. …..Through the exhibition, visitors can gain an in-depth understanding of the chemical composition, classification and recycling processes of different plastic materials, and also learn about the harmful effects of plastic waste on birds and marine animals. The aim is to let us realise that we must curtail our consumption of plastic and encourage the recycling of plastic immediately.

To enrich the educational experience of the exhibition, we have specially invited the students of the “Project We Can” to collect plastic garbage from the beach, classify them, and make different works of art using plastic garbage for display in the exhibition.”

– Introduction to the Hong Kong Science Museum’s “Out to Sea? The Plastic Garbage Project” exhibit (emphasis added)

I care a lot about the plastic waste problem too, so this exhibit was a must see for me. Since the Science Museum is huge (over 10,000 square feet), I realised that it will take me at least two hours to check out all the exhibits. I expected to get thirsty during my visit, so before my trip I asked the Science Museum on its Facebook page whether there are any water fountains there. I received an immediate reply which said “Greetings. Since eating and drinking are not allowed within the exhibition area, there is no water fountain installed.”

Oh I see! Because eating and drinking are prohibited, there are no water fountains. Following the same logic, there should also be no beverage vending machines either. So I asked “Are there any vending machines selling plastic bottled water or drinks?” This must have been a difficult question to answer, because it took them a whole day to reply this time “There are beverage vending machines on the first floor of the Science Museum, selling plastic bottled drinks, paper carton drinks and can drinks. There are recycling bins placed next to the vending machines as a means to encourage citizens to recycle waste.”

This is really weird! If there are no water fountains installed because drinking and eating are prohibited, why are there three vending machines installed? Two out of three machines sell plastic bottled water. But wait, there’s more. The very brand of bottled water sold in the vending machine was also used by the students in their “Project We Can” art project. I guess the purple bottle caps were irresistible.  The students really didn’t have to go all the way to the beach to pick up these bottles, they could have just gotten them at the Science Museum.

If you follow the financial markets, you’ll notice that the price of commodities such as oil  have plummeted over the last couple years. Plastic is made of oil. As a consequence, the recycling business globally is in trouble. In Hong Kong, where there are no subsidies for recycling and with few exceptions, no charges for dumping waste into the landfill, recycling has ground to a near standstill. Most plastic bottles, even if placed in the recycling bin, will still end up in the landfill anyway.

Not only the Science Museum, but all other museums managed by the LCSD have no water fountains. Ironically, while there is not a single water fountain or dispenser in any of these museums, there are numerous beverage vending machines. Premises which allow the installation of vending machines can share in the profits from the sales. We would like to ask the LCSD how many beverage vending machines have been installed on their premises, and if they collect profit-sharing?

We give this exhibit by the Hong Kong Science Museum a Green Wash rating.

water fountain at MoMa

Drinking fountain at the Museum of Modern Art (MoMA) in New York.

Plastic Microbeads in Scrubs

Three and a half years ago there was a plastic disaster in Hong Kong. During a typhoon, 6 shipping containers of plastic pellets were blown off a container ship into the ocean.  Dissatisfied with the government’s inaction, thousands of Hong Kong citizens took up the task of cleaning up the plastic pellets that washed up on the beaches.

In addition to accidents, the simple act of washing our faces can result in plastic going into the ocean.  The “scrub” in many brands of face and body scrub are actually made of plastic micro beads with a diameter 2 to 12 times the width of a human hair.  If plastic micro beads this small get into your eyes, they may cause infection. When they go down the drain, they cannot be filtered out by the sewage treatment plant because they are so tiny.  So billions end up in the ocean everyday and are often mistaken for food by marine life. The beads absorb toxins from the water,  the fish eat the beads, and we eat the fish. A terrific video by The Story of Stuff explains it.

If we do not want to eat plastic, we have to take the first step and stop using personal care products that contain micro beads. How can you tell if your facial or body scrub contains micro beads? Look at the list of ingredients, if you see any of these words: polyethylene, polypropylene, polyethylene terephthalate, or polymathy methacrylate, then it contains plastic micro beads.

Excited to learn that an Amsterdam-based organisation called 「BEAT THE MICRO BEAD」 developed a mobile app which helps identify products containing micro beads,  I immediately downloaded it.

I walked in the two major chains of personal care shops and identified a few brands of facial scrub.  Some brands listed the ingredients on the packaging, while others are silent as to what is actually in their products.  I tried to scan these products with the app, but found that most of them are unknown to the app.  There is a report function in the app, so you can take photos of the front and back of the products and upload them.

Since the app does not seem to cover many of the micro beads products available in Hong Kong and does not have photos, we have set up a page on Go Green Hong Kong to help identify products that contain micro beads in Hong Kong.  We invite readers to join our effort – if you spot any products containing micro beads, please kindly let us know at

Upcycled in Hong Kong


GREEN RATING  Deep Green. Upcycling an authentic flour bag into a unique tote bag.

PRODUCT RATING  Good. Thoughtfully designed and well made.


AVAILABLE AT Star Ferry Farmers’ Market every Sunday, Mapopo Community Farm, ACO Book (14/F, Foo Tak Building, 265 Hennessy Road, Wanchai)

My mother-in-law visited Hong Kong recently and I was happy to show her around. One of the “must visit” places listed in Lonely Planet is Stanley.  My mother-in-law was very excited shopping for souvenirs in the Stanley market.  She picked up a tiny cloth bag with panda embroidery on it and asked the shopkeeper, “is it made in Hong Kong?”  The shop-keeper replied “Yes, of course. And it is designed by our own in-house designer.” Pleased with the answer, she paid HKD 50 for this little pouch which can probably hold a pack of kleenex.  We walked down two shops and saw the exact same panda pouch for sale!

If you happen to be visiting Hong Kong and are looking for souvenirs which are truly made in Hong Kong, I would recommend this upcycled flour bag instead.  It’s made by Yung-jie, a retired former garment factory seamstress. She collects used flour bags, washes and irons them, then spends a couple of hours sewing the strap, the liner and zippered inner pockets as well as other features. Yung-jie’s daughter often teases her by telling her that including the time it takes to make and sell the bags, she is not even making the minimum wage!  But Yung-jie does not mind. She laughs it off and told me that she simply enjoys talking to her customers directly so that she can explain to them all the thoughtful design features she has added to her upcycled bags.

I bought one from Yung Jie about 7 months ago and have been using it almost on a daily basis – often filling it with heavy groceries.  Although the colour has faded a bit after a few washes, overall it’s holding up really well.

In addition to the tote bag above, there are many other designs such as pencil cases and backpacks. Check out the Sunday Star Ferry Farmers’ market and talk to Yung Jie directly about these upcycled bags that she makes right here in Hong Kong.

Meat Free Landfills


While strolling through a Wellcome supermarket one evening, I saw the staff removing 30 or so packs of unsold meat from the fridge, and putting them in a black plastic garbage bag. I asked whether it was going to be thrown away as trash. The friendly worker nonchalantly replied “yes”, as if it was the most normal thing in the world.

These packs of unsold meat, sitting in foam trays and enclosed in plastic wrap, will be sent to the nearby landfill. There, they will decompose anaerobically, emitting a horrendous stench and methane, a greenhouse gas at least 20 times more powerful than CO2.

In 2012, research by Friends of the Earth (FoE) revealed that Hong Kong’s supermarket chains were throwing away tons of food everyday. FoE estimated that the big four supermarket chains: ParkNshop, Wellcome, China Resource and Jusco (now renamed Aeon) combined were sending 87 tonnes of food to the landfill each day. According to FoE, “In a year, the food they throw away is equivalent to the weight of two thousand double decker buses.” Of that amount, one third is bread, vegetables, fruits and even sushi that is still edible. Two thirds consists of peel and expired food which they classified as non-edible (However, as John Oliver explains in this hilarious segment, the expiration dates set are quite arbitrary and most food is still edible well past the expiration date). Continue reading

Addicted to Trash


With stunning speed, Hong Kong has transitioned from a manufacturing hub into a post-industrial service-based economy. Few things are now made here, most are imported from around the globe or the bustling behemoth an hour away. This consumer based economy produces massive amounts of trash that remains out-of-sight and out-of-mind unless you happen to stumble across  the shrunken grandmas collecting cardboard and beer cans at midnight.

The drive to sell luxury goods and live the “good life” has blinded Hong Kong to the environmental impact of endless consumption. Hong Kongers produce 6.5 million tonnes of trash every year, more per-capita than any other developed society. 65% of it is dumped into three landfills. This is cheap, commands minimal effort or attention from the public, and requires little infrastructure investment. However, land doesn’t come cheap on the fragrant harbor, and it’s difficult to build on top of or near landfills, which contaminate soil and groundwater, and release greenhouse gases (not to mention a terrible stench). The landfills are near full capacity, and unsurprisingly the public is lukewarm about expanding or creating new ones. New solutions are needed, but what are some of the options? Continue reading

Green Common


Green Monday is a social enterprise that promotes vegetarian diets by cooperating with restaurants, schools, hospitals and other enterprises. Vegetarian diets have been widely recognised to provide both health and environmental benefits. “Green Monday” is an ingenious way to get non-vegetarians to start thinking about eating a vegetarian meal once a week. It publishes meat-free menus and recipes, hosts vegetarian cooking classes and provides educational talks on diets and nutrition. Recently, they expanded their business to retail, opening a vegetarian supermarket in Wanchai called Green Common. I dropped by one afternoon to check it out.

The decor is minimalist and cool. Organic vegetables are prominently displayed near the entrance. Some of the produce is locally sourced. Shelves inside are full of vegetarian products - gone are the days of vegetarian food being bland and uninteresting. The wide array of ingredients and seasonings from all over the world lets you experience vegetarianism without sacrificing flavour, nutrition or variety. Continue reading

GM Foods Part 2: A Tool We Can’t Turn Away From?


Spraying Roundup herbicide on Roundup Ready crops to kill weeds

In Part 1, the potential of GMOs to fundamentally change the way we grow food was explored. Of course it isn’t all upside and there is risk when transitioning technology from the lab to the field. But as GM technology is just a plant breeding tool, it’s more pressing to look at the context in which it’s being used and to what end. As of now it has been reduced to a bandaid for maintaining an unsustainable system of industrial farming. Because of this, claims that GM crops can benefit humans (by improving the nutritional content) and the environment (by reducing chemical use on farms) have not been realized.

GM crops are by current metrics safe to humans and the environment. They are without a doubt less harmful than pesticides sprayed on open fields that contaminate water supplies and nearby forests. Regardless, there are reasons to be careful, changing the complex dynamics of ecosystems will have consequences. Crops engineered to kill insects could disrupt natural ecosystems. Another concern is the unlikely possibility that the engineered genes may be passed on to other species via cross-pollination. This could spread herbicide resistance on to weeds or unintentionally kill beneficial insects.

The biggest issue is what GM technology is being used in service of – propping up our current system of industrial agriculture. Industrial agriculture involves growing monocultures or miles and miles of a single crop. While maximizing efficiency, it sacrifices the resiliency of a farm in the face of pest and plant diseases by completely destroying the ecology for the purpose of growing one crop. With only a single crop, pest and diseases can spread like wildfire causing great damage. Hence, these fields require extremely potent chemical pesticides to protect them. Continue reading

GM Foods Part 1: A Tool We Can’t Turn Away From?


Part 1 explains the history and benefits of GMOs. Part 2 will examine the risks and issues. 

Modern agriculture’s practice of growing monoculture crops with pesticides and synthetic fertilizers makes it one of the most environmentally destructive human activities. Almost nothing compares to the catastrophic levels of deforestation, toxification of water resources, and soil exhaustion that results directly from conventional chemical farming. But we need low-cost food to feed the world and therefore we need modern agriculture. Genetically engineering staple crops, to reduce pest infestation and boost their nutritional content, may be able to reduce the impact of modern agriculture, increase yields for a hungry planet, and lower rates of nutrient deficiency in the developing world.

The portrayal of DNA in popular culture unhelpfully overemphasizes its influence. DNA is not a rigid blueprint dictating our fate, but rather a library stretching beyond view, crammed with manuals describing in detail how our body works. Depending on environmental conditions, some manuals are pulled from the shelf and read while others remain untouched. Each cell carries this library within its nucleus. The function of DNA is to provide these manuals, written in a code, for directing protein creation. Proteins are multipurpose workers that do the most important tasks in the cell. Scientists can cut DNA strands and insert new, lab-made code that alters which proteins are created, thereby altering the functioning of the cell itself. Genetic engineering stripped down is simply that, cutting and pasting bits of genetic code in an effort to alter the functioning of the cell. The most difficult part is deducing if the code leads to a protein that produces the desired effect, and if so, how will it affect other cell processes. Continue reading

Soil Matters!


In Hong Kong, it’s easy to forgive the impression that we have transitioned to a post-soil society, where with enough concrete and wifi all of our needs can be met. We aren’t there yet and never will be, as soil is an irresistibly efficient way of providing nutrients for food crops to grow. It is the most valuable asset of a farm. Before we get the chance to finally appreciate soil, it may soon disappear. Agronomists predict that within 60 years global soil systems will be irreparably degraded.

Soil is a simple word that describes a complex ecosystem consisting of five essential components. Much of soil is a combination of minerals essential for plant health. Organic matter is made up of plant and animal remains that have been broken down by microorganisms, such as fungi and bacteria. Microorganisms are nature’s diligent nutrient recyclers. Soil needs to be loose to allow gases (oxygen, carbon dioxide) that are essential to the life processes of microorganisms and roots to circulate. Finally, water dissolves and transports nutrients to plant roots. Ideally, all five components are present in relative abundance. Soil composition and quality can vary widely, which is why organic farmers add compost and organic fertilisers to soil.

It may be tempting to grow crops without soil by using water-based hydroponic systems. These systems however have significant drawbacks. First, they can only provide for a fraction of our food needs. They are unable to grow large quantities grain such as rice, wheat, soya and corn that account for 60% of our diet (much of this is fed to the animals we eat). Second, they are capital and energy intensive, making them uneconomical except in circumstances where there is an abundance of both and a shortage of arable land (such as the Middle East). Continue reading


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