Gardens Above the Traffic

From street level, the Westbridge shopping centre looks like any other large building surrounded by busy roads. Few shoppers realise that six floors above them, tomatoes, herbs and salad leaves are growing in long rows. The rooftop farm began as a small experiment by environmental engineer Lila Gomez, who wanted to test whether unused city roofs could produce food without major structural changes. She expected the project to remain a technical demonstration. Instead, after local restaurants asked to buy the first harvest, the centre’s owners agreed to expand it across most of the roof.

The farm does not use soil. Plants grow in lightweight containers filled with a material that holds their roots in place while water carrying nutrients flows past them. This keeps the roof load relatively low and allows the team to measure exactly how much water the plants receive. Sensors also record temperature, wind and light levels. Lila points out that the technology itself is not especially new. What matters, she says, is adapting it to an exposed urban roof where conditions can change quickly and where maintenance workers need safe access to equipment.

At first, the team assumed strong summer heat would be their main difficulty. In fact, wind caused more trouble. Tall plants dried out rapidly and some were physically damaged during sudden gusts. The solution was not to build high solid barriers, which could have created dangerous pressure in storms, but to use lower screens that slowed the air while allowing some of it through. The team also changed what they grew. Instead of trying to copy a traditional farm, they selected compact varieties that could be harvested frequently and sold quickly to nearby kitchens.

Restaurants value the farm partly because produce can arrive within hours of being picked. However, Lila is careful not to claim that rooftop growing will replace ordinary agriculture. The quantities are far too small, and many crops are unsuitable for the system. She sees the farm as one piece of a larger food network: cities can produce certain high-value or highly perishable foods locally, while still relying on rural farms for grains, fruit and other products. For her, the strongest argument for rooftop farming is not independence but diversity.

The project has also changed how the shopping centre uses the roof. School groups now visit on weekday mornings, and office workers can volunteer for short gardening sessions. Lila initially worried that visitors might distract the technical team. Instead, she found that explaining the system forced everyone to think more clearly about why particular decisions had been made. Some practical improvements, including clearer labels on pipes and better paths between growing areas, were introduced because visitors asked questions that staff had stopped noticing.

Other building owners have contacted Lila about copying the idea, but she always begins with a warning: not every roof is suitable. Engineers must check weight limits, drainage, access and exposure before anyone orders equipment. She is pleased by the interest, yet frustrated when publicity presents rooftop farms as simple spaces that can be installed anywhere. “The attractive photographs are the last stage,” she says. “Before that comes a lot of ordinary engineering.” Her aim now is to publish a free planning guide so that future projects begin with realistic expectations rather than fashionable enthusiasm.

The farm has had to develop routines for deliveries too. Because the shopping centre is busiest in the afternoon, produce is collected early and moved downstairs before customers arrive. This sounds minor, but Lila says practical details like access times often decide whether an urban project works smoothly. The guide will also include examples from several different roof types.