Necessity is the mother of all invention. That's what led to the world's largest man-made forest adding more vegetation to its iconic skyline. Districts within the City of Johannesburg have been utilising the space on their rooftops to build planters in which to grow fruit and veg to feed the inner city. The majority of these projects are run by developers and are also used for skills development.
Rooftop gardens don't follow conventional agricultural methods but instead rely on two systems: hydroponics and aquaponics. Hydroponics is a subset of hydroculture, which is the soil-less growing of plants using mineral nutrient solutions in water.
Aquaponics is a combination of hydroponics and aquaculture (raising fish) in a symbiotic system. The fish waste is used to feed the plants as it contains the nutrients needed to grow healthy fruit and vegetables. In turn, the plants filter the water for the fish. Aquaponics uses between 80% and 95% less water than in-the-ground farming, making it a life-saver in times of low rainfall and drought. Vertical farming (growing up not out) increases planting space, and both hydroponics and aquaponics can be used, leading to bigger food yields.
The Johannesburg Housing Company is running four rooftop gardening projects on their buildings and two ground gardens in and around the CBD. They are in Hillbrow, Joubert Park, Troyeville, Newtown and Fordsburg. Crops are grown according to the season, sustainability and nutritional value, and include spinach, beetroot, onions, tomatoes, cabbage and beans, among others.
The plan going forward is to roll out rooftop gardens across the City of Johannesburg and to create a food bank for those in need. This method of farming is ultimately much easier, it's sustainable and adaptable to the surroundings and should become the norm in South Africa.
By Shawn Greyling
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