Al-Ahram Weekly Online   2 - 8 June 2005
Issue No. 745
Published in Cairo by AL-AHRAM established in 1875

May your roof be green

Rooftops lie above the din of the city, one with, and apart from, the chaos. Amany Abdel-Moneim points to their ecological potential

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Clockwise from above: Farid's kitchen garden; planting strawberries at Al-Orman School; the three-level tube system; Al-Zawya Al-Hamra green rooftops

The urban environment is ailing and, what is more, there are precious few ways in which to address its problems. Green roofs are one such way, both innovative and cost- effective, and they provide many a city-dweller with a project through which to play a part, however small, in making Cairo indefinitely inhabitable. From a more selfish perspective, plants help rid the air of pollution and cool the surroundings in summer, giving residents a uniquely healthy space of their own.

"The rooftops of many of our buildings are crowded with junk -- useless stuff, which turns them into mere dumping grounds," states Ali Abul-Fetouh El-Sherbini, director of the Central Laboratory for the Agricultural Climate (CLAC). In the meantime population explosion and the tendency to build on agricultural land have acted to limit the resources of city families and their access to healthy produce. "With a little effort and even less money," El-Sherbini says, "rooftops can be transformed into mini-kitchen gardens that produce vegetables and fruits, free of hormones and pesticides." This has been part of the drive behind recent campaigns to bring greenery to the urban environment, one of which has focussed on rooftops. "Planting rooftops," El- Sherbini declaims, "will no doubt have a positive effect on the nutrition of the poorest sectors of urban society, improving its overall standard of living." On an appropriately wide scale, "roof planting" would significantly improve the environment. Not only does it raise oxygen levels, it helps keep temperatures low. Green rooftops, El-Sherbini adds, will yield high-quality vegetables, encourage efficient use of water in an agricultural context and generate incomes.

Ain Shams University assistant professor Osama El-Beheiri, head of the CLAC Soil-Free Agriculture Research Department, for his part, points out that, while it is not new, the notion of planting rooftops has only recently been implemented. It was in the early 1990s, at Ain Shams University, that a handful of agriculture professors developed a system of growing organic vegetables to suit densely populated cities -- or rather, more specifically, the roofs of those cities' apartment buildings. But only with the help of the Food and Agriculture Organisation (FAO) was the idea officially adopted in 2001. Having helped implement it in such developing countries as Kenya, Senegal and Columbia, the FAO's assistance, El-Beheiri adds, has proved indispensable.

If the market remains small despite the authorities' efforts, he goes on, this is due to the lack of awareness of the benefits of green-roof agricultural technologies. "At the beginning, especially," he says, "the response of the public was somewhat modest." Then the Islamic preacher Amr Khaled called for environmental awareness on his television programme Sonnaa Al-Haya (Life Makers), and vast numbers of people began to show interest in joining in the project -- at a variety of levels.

Unlike "open-field", conventional irrigation, the "closed system" developed for rooftop planting makes spare -- and efficient -- use of water through an arrangement of readily available substrates -- rice husks, sand and peat moss -- that allow water to be used and re-used. "More importantly," El-Beheiri explains, "pesticides are avoided altogether, a strategy that ensures healthier produce. Another advantage of the system as a whole is that, with the produce growing on the producer-consumer's own rooftop, it involves no transportation, packaging or storage costs of any kind."

According to El-Sherbini, the project can be carried out on a very small scale: "It's easy-to-do and available to anyone." One thing it does require is that rooftops be cleared of junk or garbage that might block sunlight -- an added environmental benefit. Four to five hours of sunlight daily are necessary to healthy growth.

Expenses vary depending on the mode of implementation, El- Beheiri explains. One option (which comes at LE110-155 per square metre) involves the use of wooden tables with peat moss- or perlite-filled plastic sheets for substrates; drainage goes through small plastic hoses and a bucket. This system is suitable for leafy crops like parsley, radish and carrots but cannot be used "to generate income", as El-Beheiri explains, "rather for domestic consumption". A good business option (a set of three level tubes costs LE170-200 per square metre) comprises "wall gardens": the plants are held in plastic tubes or bags on the walls, with an automatic drainage system installed. "In both cases the main element is exposure to sunlight; no extra care is required."

With the crops reaped earlier than plants grown under normal conditions -- lettuce, for one example El-Beheiri gives, grew in two rather than three months -- the rooftop solution is both inexpensive and easy to maintain. Research to develop even more effective methods is ongoing, El-Beheiri adds: one modification of the "manual system", for example, involves placing tables on top of bolti fish tanks (CLAC researchers are now experimenting with shrimps as well) -- a mini-fish farm: "Fish water is full of ammonia and organic compounds that are harmful to fish and useful to plants. All you need is air and water pumps -- in time, you will have bigger fish and pesticide-free produce," (the whole system including pumps costs LE700-800 per 1x2 square metres). The closed system makes room for diversity: a wide range of fruits and vegetables can be grown in the same space, in the same way, and, being an example of organic farming, there is never any danger of the nutritional content being degraded.

General Nasr Farid, a resident of Nasr City, is among many beneficiaries of the first phase of the project: "I started with 20 wooden tables; now I have about 87. Over three years the whole process has cost me around LE5,000. But I'm very proud of my kitchen garden. I sell my produce and share it with my neighbours. I've successfully grown cucumbers, green peppers, tomato, capcci, mint, eggplant and many fruits..."

Institutions as well as individuals have caught on: at Al-Orman Preparatory School for girls, for example, students have planted strawberries, mint and lettuce as well as lemon trees. "This could be an important environmental step for developing countries," El-Beheiri muses. "If it's given the attention it deserves, it could mean a cleaner environment, as well as an opportunity for students, graduates and even housewives to interact with their respective communities and make some money on the side. Though the project is officially closed, the CLAC will provide anyone who needs it with professional advice. Seeds and shoots are also available at our outlets, and we provide them at very affordable prices." CLAC also provides intensive and regular courses as well as professional assistance. With a website now online,, no one with access to a rooftop has an excuse any longer. Get on with your crops.

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