Growing Food on Green Roofs: The First Step of an Interdisciplinary Approach

Abstract

Under the many available strategies for the adoption of sustainable practices, the urban agriculture emerges as a relevant alternative. Urban naturation is the vegetative treatment of built surfaces, using plants adapted to the local environmental conditions. The vegetation is a highly relevant element to the regulation and balance of extreme climatic conditions. It also affects buildings thermal comfort and energy use, when assuming functions of control regarding solar radiation, air relative humidity and air movement. Besides the role of climate control, the vegetation can also play a role in food production. The growing of vegetable crops, spices and medicinal herbs has gained the urban spaces of Brazilian cities. The growth of plants at home or in the urban environment, described as productive landscape, becomes one of the few ways of contact with the elements of nature. Therefore, the urban agriculture can create natural spaces in the urban centers, thus, promoting the comfort into two scales: the urban scale and the building scale. On the other hand, the addition of vegetation for food production on built surfaces assumes a multidisciplinary effort. It is needed to technically respond to the suitable choice of substrate and plant species, to the nutrition values of the cultivated foods and, therefore, to the building physics that supports the food production. The aims of this investigation project are: (i) to increase international partnerships in the subject (the Federal University of Pelotas, in Brazil; the Lund and the ALNARP Universities, in Sweden; the Polytechnic University of Madrid, in Spain; and the Arizona State University, in the United States); (ii) to bring information on both the building energy efficiency and the outdoor microclimate as a consequence of the green roof establishment; (iii) to generate a cultivation guide for food production on rooftops. Thus, this paper presents the first step of the research interdisciplinary approach, which deals with the construction of the Cultivation Guide for Rooftop Farmings. Through a literature review, data from 19 food plant species were compiled to inform their proper growth and management. Additionally the same data will be used as the inputs for the modelling of the outdoor microclimate and indoor thermal comfort provided by those species. Exemplifying results in the form of synthesis tables, this paper shows the data of substrate and vegetation for two vegetable species: lettuce and tomato.