The plant growth substrate must enable the plants to develop a dense root system and meet the physical, chemical and biological needs of the plants. According to international (FLL) and national specifications, the plant growth substrate must have a specific porosity, pH and granulometry, depending on the plant material and the green roof type. It must be stable in structure, absorb and retain water for plant growth and allow only excess water to be directed to the drainage system, not becoming compressed over time and allowing the root system to ventilate even when saturated with water.

The Prasini Stegi-DIADEM growth substrates are available in various types (SEM, SRM etc.), so that in each case the appropriate substrate is selected according to the type of green roof implemented (extensive-semi-intensive-intensive), the plant material and climate conditions of the area. All substrates comply with FLL specifications and carry a laboratory analysis.