Most urban residents don’t think of Boston, with its high rise buildings, multi-tiered parking garages, manicured campuses, and concrete condos as an epicenter of food production. It's difficult to look between the buildings and see the untapped potential held in rooftops, balconies, fire escapes, and empty lots. But organizations such as Top Sprouts, The Food Project, and the Green City Schoolyards program are showing Boston residents and students the multiple benefits of urban agriculture.

As urban gardens thrive in cities across the United States, they are helping to improve nutrition and reduce obesity and creating jobs that teach people about the importance of choosing local foods. And in Africa, urban farming is also improving food security and providing a solution for urban residents who face hunger and malnutrition in their daily lives.

According to the 2010/2011 State of the World’s Citites report from the United Nations Human Settlements Program, in sub-Saharan Africa, 14 million people migrate to urban centers each year. This makes growing food in cities more important than ever before. By 2020 some 35 to 40 million African urban residents will depend on urban agriculture to meet most of their food needs, as cited in “Women Feeding Cities: Mainstreaming Gender in Urban Agriculture and Food Security” by Alice Hovorka, Henk de Zeeuw, and Mary Njenga.

But fortunately, innovative urban farming projects are finding ways for people to feed themselves. As part of our on-the-ground research for the Worldwatch Institute’s Nourishing the Planet project, we traveled to 25 countries across sub-Saharan Africa, shining a spotlight on innovative approaches that help reduce global hunger and poverty. We met with farmers groups, non-governmental organizations, and policymakers whose efforts provide stories of hope and success which will be highlighted in the just launched publication of “State of the World 2011: Innovations that Nourish the Planet.”

The nearly one million people living in Kibera, sub-Saharan Africa’s largest slum, located outside Nairobi, Kenya, face numerous challenges, including lack of land ownership and access to clean water. But they are thriving. Urban Harvest, an urban agriculture research organization, is working with women’s “self-help” groups to raise vegetables on what they call “vertical farms.”

Crops are planted in tall sacks, filled with dirt, and women grow crops in them on different levels by poking holes in the bags and planting seeds. Solidarites, a French non-governmental organization, is providing these urban farmers with much-needed access to seeds, sacks and training. Today, over 1,000 women in Kibera are using this innovative method to grow spinach, kale, squash, and tomatoes with organic manure that they collect from their livestock.

Despite being some of the poorest members of society, these women were among the best prepared for the 2007 food crisis. Fresh produce from their “vertical farms” provided families with nutritious meals at a time when no food was coming into the slum.

And in Soweto, South Africa, the city’s poorest residents, who live in shacks with tin roofs and no access to running water, are also growing spinach, kale, and cabbage in their backyards. Local city governments across the country are investing in urban agriculture to help city residents grow vegetables and fruits and raise livestock.

By making communities self-sufficient, these simple, yet innovative projects can yield big benefits. They help strengthen food security and improve overall wellbeing for some of the world’s poorest people. Urban residents can also take pride in the fact that they are growing nutritious food to feed themselves and their families.

As urban farming is embraced by communities around the world, there is a huge opportunity for sharing knowledge and learning from each others’ experiences.  A local innovation that works effectively in Boston, for example, could be scaled up or replicated in other cities worldwide.

With global food prices on the rise, and the impact of climate change becoming more significant, home gardens which raise fruits and vegetables that are resistant to extreme weather and are rich in vitamins and nutrients are becoming more important then ever before.

Danielle J. Nierenberg is co-project director of the Worldwatch Institute's Nourishing the Planet project. Janeen A. Madan is a food and agriculture research intern with Nourishing the Planet.