Maintenance, operational costs, and plant performance in three extensive green roof designs from Northwest México.

Green roofs (GR) are nature-based solutions for climate change adaptation and mitigation in buildings and cities. However, few GR maintenance, installation, and challenge-solving guidelines are available for semiarid climates. We present how three case-study types of GR (urban gardens (UGR), native gardens (NGR), and wetland roofs (WR)) varied in installation costs, irrigation volumes, maintenance times, vegetation cover, survival, biomass and yield, in Ensenada, México, from 2022 to 2023. In UGR, nine edible species were cultivated to yield produce; in NGR, six native plants were planted, and four were grown in WR. UGR installation costs were 31 % and 21 % lower, but maintenance costs were four and 1.5 times higher than NGR and WR, respectively. UGR consumed 17 % more water annually than NGR and 42 % less than WR. Likewise, UGR demanded 94 and 92 % more annual maintenance time than NGR and WR. WR presented the highest survival, height, cover, and biomass values, followed by NGR (except for biomass) and UGR. Our results point to different GR solutions for distinct types of applications and users, demonstrating their versatility in design. All GR categories are suitable to reduce the ecological footprint of buildings; however, we emphasize that each GR design involves different economic, time, and challenge-solving commitments that should be considered before installation and operation. • We studied the economic, labor, and irrigation costs of three extensive green roofs. • We provide maintenance guidelines from a Mediterranean climate case study. • Urban Garden roofs demand more maintenance but can be very productive. • Wetlands and Native Gardens have high installation costs and low maintenance. • Green roofs are highly adaptable for distinct types of applications and users. [ABSTRACT FROM AUTHOR]