Rooftop gardens: Waging the environment war from your roof

The concrete ocean that Cairo has become leaves very little space for majestic trees and lush parks. The city is on the verge of explosion: Every free square meter is immediately built on and used to accommodate the city’s ever-growing population. Oxygen levels are being slowly depleted as Cairo's concrete and tar take over the few trees left along the sidewalk.

There are some free spaces that can be used as cradles of green however: the city’s rooftops. Traditionally the junkyard of lives forgotten, littered with everything from old pieces of furniture, piles of rubble, abandoned crates, old koshary containers and gigantic satellite dishes, Cairo's rooftops seem unused to the idea of beauty.

Osama al-Beheiry, professor at the Faculty of Agriculture in Ain Shams, explains that “as the buildings in the city cannot possibly be uprooted, we need to tame them into becoming greener.” With thousands of square meters of rooftops across Cairo, these micro gardens are gaining in popularity for different reasons. Al-Beheiry explains that some people feel inclined to replace the rubbish cramming their rooftops with plants, vegetable, trees or ornamental flowers to create an area of conviviality and freshness that filters the city’s noise and smells.

“The plants absorb the CO2 in the atmosphere and create oxygen,” he explains, adding that “1.5 square meters of uncut grass provides one year of oxygen for a human being.” Having a garden on the top of a building also provides the whole structure with natural insulation, as plants absorb up to 95 percent of the heat that falls on a building, through photosynthesis and evaporation.

“People won’t need to use as much air conditioning to cool their living environment anymore, and will have cheaper electricity bills,” al-Beheiry explains, pointing out yet another benefit of the aerial gardens.

But for most city dwellers, the primary attraction of the rooftop garden is the possibility of growing their own vegetables, a source of profit that is also free of fertilizers. “Most people grow leafy crops, like lettuce and herbs, because these are the crops that suffer the most from the abuse of fertilizers like pesticides and fungicides,” al-Behairy explains. Lettuce in particular is one of the most popular vegetables grown on roofs because it does not need much attention, and grows fast and in abundance. According to al-Beheiry, “a single meter square of lettuce can produce up to a hundred bunches in three weeks.”

The Food and Agriculture Organization (FAO) originally introduced the concept of rooftop gardening to the country about 12 years ago, but it has been implemented by very few people. Anxious for rooftop gardening to reach the masses, al-Beheiry has launched an awareness campaign funded by the government to develop micro gardens on school rooftops. Seventy-five schools in the Cairo governorate have already adopted the initiative, encouraging students to plant, water and care for these crops.

“I figured that nothing could be more effective than an awareness campaign in schools, because if each student tells his family about his school’s rooftop garden, then the idea will spread fast.” Of course, it can cost very little money to start up a small, modest rooftop garden with wooden crates and plastic containers, but it can become very costly for a fancy, all automatic rooftop garden.

Here are a few basic steps to follow to create an aesthetic and cheap garden on one’s own rooftop.

1.  Buy a one-meter-square wooden table that is roughly 10 cm deep.
2.  Cover the inside with a black plastic lining
3.  Fill the table with one hundred liters of peat moss mixed with perlite. The cheapest option is to use a mix of rice husk, peanut shells, sand and peat moss.
4.  Plant the seeds of the crop you wish to grow and dig a drainage hole on one side
5.  Place two bricks under two of the table legs in order to create a soft slope that will help the water exit the table through the drainage hole. Place a bucket under so as not to lose a drop of the water, and reuse it.

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