we analyzed for a case study area in the center of Madrid (Spain) consists of three main components (a production park, a plant pot factory and three greenhouses) combined with a dense hybrid program. Production park: a vital organ that is mutually beneficial to the rest of the program. It is at the same time a public park and a space for production, maintenance and treatment of urban trees and plants. Plant pot factory: a large space that houses a high-performance production area of pot plants based on a compact hydroponic growing process from seed to transplant. A conveyer belt crosses areas with different environmental conditions of humidity, temperature and ventilation according to the needs of each species in each moment of its development. During the process plants cross stations of nutrient application, disease control, transplantation or pruning. Seeds are sown in trays collocated at the beginning of the belt. The circulation is at such speed that plants are ready to harvest when transport is finished, accelerating or slowing down according to the plants conditions in each stage. At the end of the belt, plants are transplanted to the production park, sold in the greenhouse shop or used in the bath areas of the building. Beneath the production system are situated sport and bath facilities and relaxation areas; above it a restaurant and a bar and between it platforms for maintenance, workshops, laboratories, administration or with personal cultivation plots. Three greenhouses support the infrastructure. The most public one is educative; the second is the shop and the distribution point of the vegetation to the city and its citizens and the last one is a water greenhouse where used and rain water is recycled for irrigation.

Describe the critical need your solution addresses.

Our investigation during the last 8 years has been consisting of a general analysis of the production system in city centers and a local analysis of a potential area in the center of Madrid. An exhaustive study is done of the hydroponic production system and of the atmospheric conditions the plants need in every phase of their growing process. A catalogue is created of suitable plants that filter contaminating components (f.e. Dracaena Sanderiana filters xylem and formaldehyde, ivy filters benzene and formaldehyde), that are medicinal or therapeutic (f.e. sage avoids inflammation, aloe regenerates cell structures) or that just are decorative. Also a catalogue of trees is made, in this case adapted to the conditions of Madrid. Parallel the coexistence and mutual positive interferences of the production system and a public program (bath and relax areas, sport facilities) are analyzed. Finally, a rough calculation of the economic feasibility of a possible implementation in Madrid told us to work with an area of 1ha for the production park, combined with twelve conveyer belts of about 500 linear meters for hydroponic plant production. The remaining 2ha of the plot are used for a hybrid and dense program.

Until today most of the investigation is done by Castillo De Groote Architects. Three biologists, an economist, an external architect and two tree-nursery-men have been supporting the development of the project with information, knowledge and ideas. No money has been available for detailed studies. The project has come to a stage collaboration with specialists and scientists is necessary. Besides for that purpose, the prize money will also be used for the promotion of the project in different cities combined with the search for suitable plots with the ideal infrastructural, climatic, economic and political conditions and the search for investors as are city councils, real estate developers and companies concerned with ecology or vegetation production and sale. And hopefully one day the project will be constructed.

Explain your initiative in more depth and its stage of development.

- A contribution to the improvement of the planet (environmental benefits) of the city centers (avoids the escape to the green periphery), of the personal consciousness (involvement and education) and of the economic situation (financial benefits of vegetation production).

- A living organism that extends itself over the city, taking advantage of successive production cycles of the vegetation. This means a progressive multiplication of green surface in the city and at the same time the increase of its environmental conditions.

- Improvement of the urban climate: air humidification, temperature regulation (reductions of 1 to 4°C in summer), CO2 store and O2 liberation (approx. 7 tons a year), dust and toxic gases capture, water regeneration and purification, and noise reduction.

- Existing technologies used in tree-nursery. Hydroponic production developed a.o. by professor Ruthner.

- The plants on the balconies and terraces or the trees in the streets and the parks.

- Preserving and strengthening disposable voids can avoid homogeneous cities offering at the same time a natural and open environment and an urban context.

How does your strategy and approach respond creatively and comprehensively to key issues?

Since 2000 Castillo De Groote Architects has been working on several projects related to sustainable architecture and urbanism in Spain, Belgium, The Netherlands, Italy and Brazil, always in close relationship with local engineers and specialists. They have won several national and international competitions.
With their project “urban greening and economic catalyst” they won in 2000 the first prize in a competition organized by the Government of Madrid, the Metro of Madrid, the Escuela Técnica Superior de Arquitectura de Madrid (ETSAM) and the Università Politécnica di Milano. This year they have won an award in the international competition Holcim Awards for Sustainable Construction, organized by Holcim Foundation. In 2001 and 2005 they received a research fellowship of respectively the Comunidad Autónoma of Madrid and the French Government.