Rooftop Farms Could Feed City Slickers
They’re not likely to replace the large-scale farming anytime soon, but rooftop agriculture projects are sprouting all over the world these days. The basic idea is brilliant: there’s a huge demand in urban areas for fresh produce, particularly organic goods – but land costs in urban areas make urban farming completely nonsensical from an economic point of view. There’s one patch of land that’s usually not being used, however – the rooftop.
There are basically three ways of doing rooftop gardening. The easiest and simplest way is also the most inefficient – container gardening, where the rooftop is just used as a handy place to have lots of bins for growing crops. With a larger investment (and a stronger roof) it’s possible to fill the roof with a drainage system, a soil layer, and just plant crops in rows as though you were on the ground. And for rooftop gardeners who are serious about maximizing yields, it’s possible to deploy full-scale rooftop hydroponic systems, squeezing remarkable yields out of the rooftop environment. Hydroponic systems also dispense with the need for soil, which is tremendously heavy, making them more practical for rooftops that cannot bear a significant load.
The benefits of rooftop gardening are many. Most obviously, the building owner and/or the building tenants have a supply of fresh produce throughout the growing season, or even year-round with a well-designed system in the right climates. Whether growing herbs or organic tomatoes, this can be a serious benefit to the residents of a building. Produce can also be sent directly to local markets, turning the rooftop into an unlikely source of secondary revenue generation. A rooftop garden also can provide building residents with a cool, green place to spend time during hot days; commercial growing operations on rooftops can even employ residents as part-time gardeners. More generally, rooftop gardens cut down on the heat island effect of cities and remove pollution from the air. They also can serve as greywater recycling centers, since wastewater from the building can be easily routed up to the garden; most plants do just fine with greywater.
There are challenges facing the rooftop gardener. High winds and high temperatures are often a problem; windbreaks and heat-tolerant crops, among other solutions, have to be deployed in the rooftop environment. Pesticide use in densely populated areas can be a problem, and many rooftop gardeners go organic for this reason – and roof growers find the higher prices their organic crops command to be a welcome bonus. Liability concerns are a more difficult hurdle to overcome – for some reason, insurance companies get antsy when dozens of people are wandering around a rooftop ten or a hundred stories above the pavement! As rooftop gardens become more prevalent, however, insurance companies are climbing the learning ladder and will often have mitigation strategies (barriers at the edge of the roof, etc.) that can cut the expense.
I’ve only touched on this topic – there are people who devote entire careers to rooftop gardens. You can read a lot more about rooftop gardening and its potential at the Rooftop Gardening Source, among other places.