GREENING OUR CITIES

The Rooftop Revolution

Once wasted space, rooftops are now seen as the key to greening our cities

By Heath McKenzie, Australian Growing Solutions

We know that a fresh approach is needed for our cities to remain habitable in the face of a changing climate and increased temperatures due to the urban heat island effect. We also know that people are happier and more productive in the presence of greenlife.

The population of our cities is expected to increase dramatically over the coming decades, with many people choosing to live close to where they work, shop and socialise. Housing affordability is also pushing people into smaller and denser residential spaces.

So how do we incorporate green spaces into our cities while still allowing for increased residential and commercial space? We can start by covering the hard surfaces of our buidings in plants.

Increasingly, areas once thought of as utility spaces are instead being used for green space. Rather than having concrete wastelands collecting heat from the sun, rooftops can become productive and attractive gardens and act as retreats for occupants of the building.

Converting these areas into gardens can also assist in capturing rainwater before it enters our stormwater system, using that water to irrigate plants instead.

Architects and developers have adopted this mentality and are designing buildings with plants as a major design element.

At AGS, we have been making potting mix blends for rooftop gardens for over ten years, but there has been a noticeable increase in the demand over the last few years. The nature of these mixes can vary greatly depending on several factors such as the type of garden, engineering speciÿcations and the species of plants being grown.

Modern rooftop potting mix substrates contain a large amount of mineral ingredients such as scoria, zeolite or sand. These minerals don’t break down as quickly as organic materials like pine bark compost or coir fibre therefore reducing the need for topping up garden beds. However, using mineral ingredients drastically increases the weight of the substrate which can be an issue if not addressed at the planning stage.

By combining mineral and organic ingredients, a rooftop substrate can be a long lasting product and still contain the beneficial bacteria and funghi that exist in composted pine bark. This provides an excellent environment for growth and general plant health.

These rooftop spaces, along with greenwalls, will enable us to transform our bustling metropolises into pleasant and healthy environments for living and working.

Rooftop substrates

Greenwall substrates

Fertiliser and wetting agent

AGS have a range of growing substrates for rooftop gardens and green walls. For more information, contact us on 1800 709 588 or head to our website.

www.agsolutions.net.au