Quality of pink evening primrose (Oenothera speciosa Rosea) improved by application of vermicompost and rice hull in green roof medium

Green roofs are a part of efforts to make the cities more sustainable and it is one of the modern solutions for urban problems. The physical development of cities led to loss of the natural environment. Therefore, the development of green spaces plays an important role in human life. In order to evaluate the effect of some culture media on yield of “Oenothera speciosa Rosea” in green roof situation, a factorial experiment conducted based on a complete random design with vermicompost (0, 5, and 10% v/v) and rice hull (0, 7, and 14% v/v) factors in three replications. The results showed that vermicompost treatment has a positive significant effect on the number of flowers, daily flowering average, flower diameter, stem diameter, root volume, fresh and dry weight of shoots and roots and soil humidity. Also, in most measured traits, it showed a positive effect compared to control plants. In this research, vermicompost (10% v/v) mixed with rice hull (14% v/v) improved quality and quantity traits of pink evening primrose. Then, overall results showed that this mixture can recommend as a medium for evening primrose in the green roof.