Sagene Rooftop farm
In the city of Oslo on the roof of Sagene Samfunnshus vegetables, herbs and flowers are grown in raised beds covering a total area of 125 sqm. The project also includes a biodiversity island where local wild plants are being used to create a colourful habitat for insects, such as butterflies and bees.
A solution to divide the total load of the garden has been engineered, and a special blend of lightweight ecological soil is being used to make sure that technical load carrying capacity of the roof is not exceeded.
The rooftop garden at Sagene in one of the first in its kind and developing the project has already brought a lot of knowledge and experience on the technical, economic, biological and social aspects of urban farming.
An important contribution to climate goals, sustainable food and increased biodiversity
In Norway, we import more than half of the food we eat. Urban farming reduces the need for transport, refrigeration and packaging of food. To make it easy one can say that 1 kg of local produce avoids on average 2 kg of CO2 emissions.
In addition to growing food, green roofs such as roof gardens have important other benefits. Green roofs work like a sponge, they absorb and retain rainwater avoiding the use of the sewage system. The roofs contribute to cleaner air, turning CO2 into oxygen. They reduce noise levels, but most of all they look incredibly good and create a space for citizens where they can relax, meet each other, grow food together and learn to become an urban farmer.
Solving technical challenges: when biologists meet engineers
- 3 different zones with different substrate depths
The weight has been divided over the roof to optimize the bearing capacity of the roof. Food will be grown in several substrate depths of 6 cm, 25 cm and 30 cm. Crops have been chosen in function of these depths.
- Rooftop soil based on volcanic rock
A special blend of rooftop soil has been created. This soil is extremely light, 500 kg/m3 dry and 1000 kg /m3 wet. One of the ingredients in the mix is pumice, natural volcanic rock. It adds oxygen to the soil, stores water and keeps the nutrients in the root zone.
- Biodiversity Island with seeds collected in their natural habitat
One area with 6 cm of a substrate will be planted with wild plant species that can be found in the Oslo area in their natural habitats. This creates little paradises for birds, butterflies, insects and a colourful view for the people passing by.
- Drainage system
A technical drainage solution is used under the soil to store up to 20l/m2 of rain to water the plants from below and to guide the excess water quickly to the drain in case of heavy rainfall.
The project has been financed by Grønne Midler Sagene and Sparebankstiftelsen.
A group of volunteers has developed the project on behalf of Økologisk Norge. This means making sure that the roof is strong enough to carry the garden, procuring the materials such as rooftop soil, drainage systems, sustainable wood and finally coordinating the construction. The daily operations of the garden will be coordinated by Økologisk Norge and will be delegated to a group of future city farmers interested to join.
Project Group: Kristin Føyn Føyen and Jo Deketelaere (project coordination), Didrik Føyn Føyen (construction), Pierre Gould (engineer), Alette Elvenes (gardener), Kirsten Marthinsen (biologist), Doriane Happel (landscape architect), Stein-Ivar Måseidvåg Gamlem (lawyer), Janeth Rojas (photography), Ida Schou Brandis and Ginta Solyte (daily managers of the roof garden).