Green Roof Substrate Composition

Greenhouse trials presented here show that relatively minor changes to green roof substrate composition can have major effects on plant growth physiological performance and drought tolerance.

Green roof substrate composition.

Proportions of components vary among substrates based on target vegetation green roof type and other considerations. Growing substrates for green roofs are typically composed of a mix of inorganic mineral and organic components. Better green roof management for maximum benefits will require characterizing quantifying and understanding the impacts of plant species and building attributes such as aspect slope height and heating on substrate performance and should be considered for future research. He notes that extensive green roof soils are typically between 3 and 6 organic by mass but that additional organic matter can be added initially to help to establish young plants.

Whc indicates how well the growing substrate retains water whc should be 35 or greater for an extensive green roof and 45 for an intensive green roof up to a maximum of 65. Measured substrate parameters were. They can include scoria ash pumice sand coir pine bark porous chemically inertfoams and even recycled materials such as crushed bricks and roof tiles. Whc will vary inversely with afp above and an acceptable balance of the two must be achieved.

Therefore it has been found that green roof substrate can be optimised for specific climates or service provision.