Proper soil selection is critical to the long term benefits of the living roof.
Roof garden soil depth.
The following are some of the characteristics of the soil for the green roof.
Options for your rooftop garden.
Soil s saturated weight can reach 120 lb ft 3 7 5 kg m 3 which is far too high for roof gardening.
This rooflite soil system supports lawn grasses that require deeper root space thrive on a soil with plenty of finer particles the precise amount of organic matter.
The targeted saturated weight of roof top growing media should be 48 65 lb ft 3 3 4 kg m 3.
If you re considering a rooftop garden there are a couple of directions you could go in.
B extensive medium depth roof garden system a medium depth planting system soil depth of 4 to 8 where recommended plants include sedums herbs grasses and other vegetation which can grow in this depth of media.
Fully planted green roofs where the roof is covered with soil and the plants are in the ground make great environmental sense but they are too difficult for homeowners to undertake on their own.
It depends on what you want to grow but generally speaking a depth of 20 25 cm 8 10 inches suffices to grow many vegetables and herbes but do investigate if your roof supports such a weight because a rooftop garden can become very heavy when it s soaked with water.
Rooftop lawns are semi intensive green roofs with a total depth of at least 8 inches.