This article points out the world's most outstanding urban gardens on rooftops, their advantages and challenges and how to create one.
More and more hotels, restaurants and communities of neighbours are installing urban gardens on their roofs.
Hotels roofs, restaurants or buildings of neighbouring communities can be a good place to grow fruits and vegetables. So they are being used in more and more cities around the world, obtaining benefits from the environmental, economic and social advantages of urban gardens on their roofs. This article points out the world's most outstanding urban gardens on rooftops, their advantages and challenges and how to create one.
The most outstanding urban orchards on rooftops in the world
The famous New York skyline, drawn by its skyscrapers on the horizon, includes fruits and vegetables thanks to Brooklyn Grange, an urban garden located on two rooftops of the popular neighbourhoods of Brooklyn and Queens. According to their managers these gardens produce in its 10,000 square meters a wide variety of crops, apart from having laying hens and 30 hives that manufacture more than 700 kilos of honey a year. It is the best-known urban vegetable garden on the roof, selling its products to restaurants and individuals and receiving thousands of visitors annually for educational activities and workshops.
An urban garden on roof provides vegetables and an energy saving of 14% of the building by having the roof better insulated.
And it's not the only one. More and more restaurants grow their own vegetables on buildings’ roofs in Paris or London, and more and more communities of neighbours or individuals are setting up gardens on the roof.
There are installations that may cover the whole roof, by using tables or modular systems that fit within the possibilities of each building. This also works in hotels such as the Waldorf Astoria in New York or the Fairmont Royal in Toronto, which use the products obtained to feed their customers.
How it works in Spain
In Spain, the most well-known urban garden orchard is on the Wellington Hotel in Madrid, where they grow more than 300 m2 of vegetables and various aromatic herbs, and you can visit freely making a phone appointment.
In addition, initiatives have been launched in a wide range of fields, from experimental gardens in universities, such as the Autonomous University of Barcelona, to educational gardens on roofs of schools, such as Escolapies de Figueres (Girona).
In Madrid and Barcelona studies are being carried out to use the roofs of their buildings as a contribution to the naturalization of cities. The Madrid Más Natural project values the creation of green roofs and orchards on roofs.
Advantages and challenges of urban gardening on roofs
Its proximity and accessibility are the most obvious advantages of urban roof gardens, but they are not the only ones. They function as thermal and acoustic insulation and reduce the energy expenditure of the building by up to 14%, since it considerably decreases the temperature in summer and contributes to greater insulation in winter.
They help reduce stress, educate children and their owners can eat healthier food, it help to strengthen ties between neighbours, involve an expansion of urban green areas and an increase in self-sufficiency, reducing carbon dioxide (CO2) emissions from transport as the vegetables are produced in situ.
As for its challenges, we have limitations to cultivate with a much reduced depth of soil. Obviously to design a building with a roof top garden has a higher initial investment, although it varies alot depending on its complexity and layout of the building, and obviously it requires more maintenance.
Like any crop in containers, it is necessary to be more aware of its irrigation and to maintain sufficient nutrients in the soil.
Although these problems can be solved, by installing a good automatic irrigation system and using good fertilizers.
We have to add to the previous challenges the "heat island" side effect of cities, where higher temperatures may complicate the growth of some crops, especially in climates such as Madrid or Barcelona. Although these higher temperatures can be turned into an advantage if the right types of crops which adapts to whatever climate we may have.
How to create an urban garden on the roof
The initial problem is for us the architects to convince property developers of the different advantages of installing an urban garden on the roof, arguing the different benefits obtained from the use of roof gardens as explained above.
As for the type of plantation, it is recommends species that require a lower depth of soil such as lettuce, garlic, aromatic herbs, etc. We could also consider spinach or strawberries, and with a better installation we could even go for tomatoes, eggplants or pumpkins.