Plant facilitation in rooftop agriculture: disentangling plant interactions for sustainable crop production on extensive green roofs

Urban Farm DB summary

This study investigated plant facilitation in rooftop agriculture in Toronto, Canada, testing whether live Sedum could improve bush bean performance on 48 extensive green roof (EGR) modules under high and low watering regimes. Water availability had a greater influence on bean performance than planting design, with beans grown with artificial Sedum under high watering showing the highest yield, while performance declined significantly under low water, particularly with live Sedum. Contrary to hypotheses, live Sedum did not consistently facilitate bean performance, suggesting potential competitive interactions may have outweighed any stress-ameliorating effects. These findings indicate water management is the main management variable for crops on EGRs.