Whether the space is small or large, on the 2nd floor or the 15th, on a historic building or on the most modern building in town, our urban farms manage to take root in all kinds of environments and in no time! The secret behind this flexibility? MicroHabitat’s vegetable gardens differs from green roofs and thus avoid many of the constraints of this type of installation…
Let’s explore the 4 main differences that distinguish Microhabitat vegetable gardens from classic “green roofs”.
1. Impact on the structure
A green roof project requires significant additions of coating, protection and drainage elements to accommodate the soil and vegetation that accompany it. All these elements impose an important weight on the structure of the building and can affect its resistance and stability. This constraint can represent an important barrier for many buildings, as they do not always have the necessary structures and foundations to support the project.
At MicroHabitat, our urban farms are composed of geotextile pots, an extremely light technology that imposes much less weight on the structure and its bearing capacity. The weight is limited to that of the soil and the plants, while no other material (wood, aluminum structure or other) is necessary for the installation of the pots. The pots are safely placed on a protective membrane and no structural modifications are required for the implementation of a project, so there is no risk for the roof membrane and the building.
Thus, most properties can be eligible to host an urban vegetable garden!
A green roof project requires a considerable monetary investment from the owner. Costs related to the membrane, irrigation system, green roof, labour and plants can total up to $120/square foot if you use experts in the field (1).
For gardening projects in pots, this cost is divided by 5 and comes to a total of about $25/square foot, while also benefiting from expert guidance. In addition to greening the roof, the project allows the surrounding community to be fed with fresh, ecological and locally produced products!
The complexity of installation differs greatly between the two types of projects. As mentioned above, a green roof project will have more impact on the building structure. The deployment of the latter will therefore require permits, possibly certification, compliance with municipal regulations, more planning and the assistance of an architect.
On the contrary, the installation of MicroHabitat’s geotextile pots is only subject to the verification of a structural engineer to attest to the roof’s bearing capacity. Since no structural modifications are required, the implementation of a MicroHabitat urban farm project is simple and does not require a building permit.
4. Depth of soil
When it comes to growing vegetable plants, the depth of soil becomes an important factor. Plant growth is highly dependent on the amount of space the roots have to grow and draw the nutrients they need to thrive. Typically, a green roof has a soil depth of 6 inches (2), which is sufficient for growing grasses and short ornamental plants, but not very interesting for food production.
If the goal is to provide a food-producing space for the green roof, an “intensive” type of roof will be installed, with a depth of 8 to 12 inches (2). This type of project, however, has a much higher cost, requires larger installations and places greater stress on the building structure.
MicroHabitat geotextile pots allow a depth of soil of 12 to 18 inches, which favors optimal root development. It is thus possible to produce a wide variety of vegetables such as eggplants, peppers, root vegetables… And even tomato plants reaching a height of 7 feet!
Let’s be clear: green roofs are great initiatives for water retention, urban greening and building insulation. However, as beautiful as these projects are, certain constraints related to their installation can slow down many homeowners to embark on the adventure.
However, this does not mean that urban agriculture should not be considered! By strategically placing geotextile pots, any homeowner can transform their roof into a nourishing garden, and at a lower cost!
Would you like to cover your roof with herbs, vegetables and greens in pots?
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