Can Africa's urban farms go vertical?

by Esther Ngumbi
Thursday, 21 May 2015 04:15 GMT

A worker harvests fresh produce from a tower at Sky Greens vertical farm in Singapore July 30, 2014. Vertical farming could be a solution to the growing food needs of Africa's cities but the practice is yet to take hold. REUTERS/Edgar Su

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Urban farmers are stepping in to provide food for Africa's ballooning cities - but vertical farming is yet to take hold

The New York region is set to welcome one of the most impressive indoor urban farming units in history.  Known as Aerofarms, it is the latest in a movement known as vertical farming that utilizes abandoned buildings, warehouses and skyscrapers to grow food.

Sophisticated technology based on LED lights, water, nutrients and air dispenses with the need for soil and sun, to grow vegetables for expanding urban populations.

But while the movement is taking hold in cities from Chicago to Manhattan to Singapore to Miyagi Prefecture in Japan it has barely debuted in the megacities of Africa, where the need for safe, nutritious food is urgent.

Africa’s urban growth rate is the highest in the world.  At 3.5 percent per year, it is double the world average.

Nairobi, the capital city of Kenya, is home to almost 3 million people and its population is expected to rise by 77 percent by 2025. The urban population of Dar es Salaam, the capital of Tanzania, is expected to rise 85 percent in the next 15 years. 

The proportion of the poor in cities is also growing, and African governments are struggling to keep up with rising demands for improved water, sanitation, housing, transport, jobs – and food. 

Increasingly, urban farmers are stepping in to fill the gap.  They grow foods close to the big city markets with whatever natural resources are available.  Unfortunately, their options are limited, especially when it comes to accessing clean water. 

As a poor student at Kenyatta University in Kenya, I experienced the direct results of this reality.  The only food I could afford was Sukuma Wiki, the most commonly eaten leafy vegetable around. I ate it every day of the week, and was often sick.  As it turns out, the greens were most likely grown using contaminated water.

In a study published by East African Medical Journal, scientists discovered that the levels of fecal bacteria in water used for irrigating crops and washing vegetables in markets was dangerously high.

Even worse, such cases of food contamination are widely found, as most wastewater generated from urban centers goes untreated into the surrounding environment.

The challenge of growing enough healthy food for Africa’s burgeoning cities is huge. At the same time, the stresses of climate change, and the declining availability of arable land and fresh water are challenging conventional agriculture as never before.

Africa needs to move farming closer to urban population hubs, grow more with less, and develop farming technologies and practices that ensure food safety. Doing so will take innovation, investment and collaboration. 

Vertical farms offer one promising option for meeting these challenges, and we already see modest versions in some African cities.  For example, in Nairobi’s Kibera neighborhood-the largest slum in Africa-many residents have taken to urban sack farming. 

Instead of the trendy rooftop gardens or skyscrapers farms, these vertical farms are simply tall sacks filled with soil. Vegetables are grown vertically through holes poked at multiple levels of the sacks, and provide needed nutrition for poor households.

At the other end of the spectrum, innovators in South Africa are proposing sophisticated indoor farms, including an architectural model for vertical hydroponic farm in the Old Pretoria West Power Station. 

Calayde Davey was a Masters student at the University of Pretoria when she came up with the idea. Although her 2010 proposal won a prestigious international award, it remains unfunded.

We need to turn such ideas into reality. In the megacities of rich countries, investors are beginning to count on vertical farms as viable businesses, and vertical farming  is increasingly viewed as a desirable career.  In fact, Yahoo listed it as one of five careers of the future.

Granted, vertical farming is not without its own unique set of challenges—especially for Africa.  We’ve already mentioned one – clean water.  However, some vertical farming technologies use a fraction of the water needed in irrigated agriculture, potentially conserving this precious resource.

Access to energy is another challenge, as vertical farming is a huge consumer of electricity.  Yet many cities in Africa experience frequent power cuts making it hard to reap the benefits of vertical farming.

Africa could tackle this challenge through developing sustainable innovative energy production sources to power up these urban farms. The good news is that Africa is in the midst of an energy revolution, bringing on line new energy sources and collaborating with partners such as the US Agency for International Development to ensure that African countries can generate reliable and sufficient energy to meet their ambitious growth plans. 

Growing enough healthy food to supply Africa’s exploding urban populations is a grand challenge, akin to others previously posed by philanthropists and governments.  Now is the time to forge the creative partnerships between African entrepreneurs, Western vertical farming pioneers, social impact funders, and corporations to develop economically rewarding but also safe food solutions for Africa’s cities.

Esther Ngumbi (@EstherNgumbi) is a post-doctoral researcher at the Department of Entomology and Plant Pathology at Auburn University in Alabama. She serves as a 2015 Clinton Global University (CGI U) Mentor for Agriculture and is a 2015 New Voices Fellow at the Aspen Institute.