There are so many great reasons to build your own rooftop garden, and yes… that goes for all you city dwellers too! With a large number of the North American population living in apartment buildings, with no yards or balconies, the idea of a garden just seems out of reach. However, growing plants and food on your rooftop is actually much more plausible than you’d think. In fact, most European cities caught on to this trend long ago, growing rooftop gardens on many of their buildings and constructs, as part of an environmental initiative.

Whether you want to grow a garden on your roof as an active response to climate change, or simply because you love the taste of fresh, home-grown (or in this case– roof-grown) food, the advantages of having a rooftop garden are far and wide. Not only helping to reduce your carbon footprint, a rooftop garden is aesthetically beautiful and saves you money in ways you may not have thought of before.

3 Types of Roof Gardens

1) Extensive living roofs

Extensive living roofs are practical if you have a shed, garage or even a dog house that you want to make full “green” use of. These types of roofs are lightweight, easy to maintain and require only about four inches of soil.

2) Semi-extensive living roofs

In order to support a greater variety of plants, (or goats), a semi-extensive living roof is required. This type of roof is necessary for more decorative gardens with deeper soils. With the increased depth of the soil, the heavier your garden will be on the roof. Obviously, to avoid any nasty problems, like roofing damage, be sure that your roof is a solid enough structure to support it. Otherwise, this type of roof garden is relatively easy to maintain. (Less so, perhaps, with goats on it.)

3) Intensive living roofs

When talking the mother load of gardens, intensive living roofs are the only realistic option. These types of gardens require large, strong support structures, especially considering that wet soil can weigh nearly eighty pounds per square foot. These living roof gardens will necessitate a lot more care and maintenance than the other types of living roof gardens.

The Essentials for Having a Rooftop Garden

1) Vegetation needs three main things to grow: sun, soil and water. With the roof being your closest bet to direct sunlight, you’re already one third of the way there. Given that rain is yet another natural provider for plant life , watering is pretty well taken care of as well. Soil, on the other hand, may vary depending on the type of plant, and the type of roof, so be sure to make adequate inquiries on what the plant’s soil needs are.

2) Install a waterproof membrane over your roof in order to prevent any water damage to your ceiling. Thermoplastic sheeting or rubberized asphalt are both good, but make sure they are durable. Having to dig up your garden to replace the membrane isn’t something you want to be doing very often.

3) Once you have your waterproof membrane, your next layer should be a filter sheet. This will allow any extra moisture to drain off the roof.

4) After the filter sheet, get yourself a proper moisture blanket, so that the roof garden can retain the right amount of moisture to support itself. You can find trays to put your plants in, which have grating on the bottom, in order to allow the plants to drain properly. You can also build a simple wooden frame on the outside to protect them.

5) For your final layer, add your soil, substrates and seeds. Be sure that the soil is lightweight, and can both drain and retain moisture. Perlite is very useful as it lightens soil and also helps with water drainage.

Overall Benefits of a Rooftop Garden

Not only does having your own rooftop garden or green roof beneficial to the environment, in that it reduces the presence of toxins in the environment, absorbs pollutants in the air and water, and produces oxygen; it can also be a great investment, significantly reducing your heating and cooling bills throughout the year. Your rooftop garden will give your roof an extra layer of insulation in the winter and keep it nice and cool in the summer. So whatever your reasons for considering a rooftop garden, it is definitely worth the effort, for you and for a better environment.