Roof gardens are both aesthetically pleasing and functional. A roof garden can provide temperature control, architectural enhancement, hydrological benefits, and of course food. In some instances they can even be wildlife habitats. Planting a roof garden can have many advantages. For instance, on a warm day it can cool the room below. It can provide insulation from the cold during the winter. Roof gardens are required in Germany to retain water from evaporating. It will prevent flash floods from occurring. Three basic types of roof gardens exist. The main differences among the three are marked by the maintenance they require, the depth of the soil, and the type of plants that can be supported by the roof.

Extensive Roof Garden

This type of roof garden is easier to maintain than the other two because it uses shallow soil. Extensive roof gardens, which are lightweight, can easily be installed on small extensions of the home like garages and sheds. The number of plants you can grow on these types of roof gardens are limited despite the ease with which you can maintain them; additionally, they have the least aesthetic value. Lichens and mosses can be easily grown in an extensive roof garden. Surfaces like metal, glass and plastic are ideal places for lichens, which are symbiotic organisms, to colonize. Mosses, which are small small green plants, do not depend on large amounts of nutrients for survival. As such, rainwater alone is sufficient for these plants, which cling to walls and stones.

Semi-Extensive Roof Garden

These roof gardens, which have deeper soil, are capable of supporting a greater variety of plants. It can therefore be decorated more easily than the extensive roof garden. Due to the heavier soil, semi-extensive roof gardens must be supported by stronger structures. Sedums, succulents that store water in their tissues, are ideal for this garden type. Although they can die or turn patchy during times of drought without proper care, sedums do not require watering every day. On a semi-extensive roof garden, you can also plant wildflowers that can grow without any maintenance.

Intensive Roof Garden

Because they can support elaborate arrangements as well as trees, intensive roof gardens require large, sturdy structures, Because most homes are unsuitable for roof gardens of this type, they are more commonly found on top of roof decks and concrete buildings. There’s no limit to what you can plant in an intensive roof garden, so long as the structure of the building can support the weight.

About the author: Megan Barlow helps others learn how to live more eco-friendly lives. Learn more about sustainable living at her blog on Green and Sustainable Building.

This article was first posted at Three Roof Garden Variations.