Grow it on the roof, sustainably

Many Australians have discovered the rewards of vegetable gardening, including those of us who choose to do it on the roof. Food production is a great way to get even more value from a green roof.

food on roof burnley

Producing food on a green roof takes good design, and some of your time. Good design is important because green roofs can be tough places for herbs, vegetables and fruit to grow. Even at ground level, they tend to be thirsty (for water) and hungry (for nutrients). On the roof, solutions can be as simple as selecting the best substrate mix and depth, or as sophisticated as an aquaponics system (the subject of a previous post).

Of course, it is also important to select appropriate plants. Plants will vary in their ability to cope with the high winds and other stresses on a roof. The most suitable foods for growing on roofs are herbs such as basil, parsley and chives, because they are relatively resilient. Even so, given the right conditions and care, a range of vegetables and fruit can also be produced.

brook grange

Once it’s up, the garden will need weekly attention to stay productive. For many gardeners, this is the fun part! The main tasks are watering, harvesting and, occasionally, applying fertilizers and re-planting.

While you should keep your plants productive and healthy, it is very important that you keep the environment healthy, too. This means doing what you can to use water sustainably. This could mean using rainwater harvesting methods, or simply avoiding watering in the heat of the day and adhering to local water use guidelines. Fertilizers should also be used sparingly, so that no polluted runoff leaves the green roof. This helps to protect local rivers and creeks.

Contact us if you would like to read our fact sheet on this topic. We also offer workshops and expert talks.

Paul Richards, Do it on the Roof

Sustainable urban food production: a challenge..and opportunity in 2015

One of our key challenges today is to ensure that when we inspire people to garden on the roof, on balconies, on walls and on the ground, the type of gardening we promote is sustainable.
At Do it on the Roof, we find Australians are more and more interested in gardening, growing food and connecting to nature. People want to bring nature back into the city. People in cities want to grow food.
And now people are excited about growing gardens – and food – on roofs. Property developers know this. Across Melbourne, body corporates are looking to retrofit existing roofs with plants.The challenge is to ensure that good intentions translate into great environmental outcomes.
In the last thirty years, common knowledge of weeds and nutrient run off and their impact on the wider environment has greatly diminished. There is a spreading misperception that all species of vegetation are beneficial to the environment in every situation. In fact, growing weeds and creating high nutrient run off can damage critically threatened ecosystems and harm our waterways.
But the interest in gardening among the community and the appetite for information about sustainable lifestyles can be leveraged to overcome this challenge.
green roof peopleGardening sustainably and ethically, based on an understanding of your impact, is not hard to achieve. It can be achieved by following a few basic guidelines that help gardeners to garden rewardingly and sustainably.
Sarah - In Garden professional
Over the next 5 weeks, our experts will be posting a weekly series on sustainable gardening and food production on city roofs. In fact, we’ve already started – check out our recent post to find out about the opportunities in aquaponics.
Coming up next is our advice on what to consider when getting started growing food on the roof.If you are interested in expert talks on sustainable urban gardening, get in touch
Shelley Meagher, CEO

Surf, turf, and a healthy earth!


Growing vegetables and herbs on your green roof can be very rewarding, particularly if the plants are kept well-watered and well-fed. But if polluted water runs off your roof, watering and feeding these plants can be risky for local waterways.

So, how do you do right by your plants and the environment?

One great design solution is aquaponics. Aquaponics combines two approaches to food production; fish farming (Aquaculture) and growing plants in soil-less systems (Hydroponics).  Plants and fish are produced in one productive, recirculating system.  Aquaponics not only adds an extra food group to your green roof, it contributes to a healthier environment too.

Its environmental benefits are particularly important when it rains. An aquaponics system captures and stores stormwater; the amount captured depends on the amount of rain and the system’s storage capacity. Something that sets an aquaponics system apart from other green roof designs is that it can otherwise be kept as a closed loop.  This means that less nutrient-rich runoff reaches local waterways, which helps to prevent problems like algal blooms.

There’s also good news when it doesn’t rain. Aquaponics systems use water very sustainably, particularly compared to traditional, ground-level gardens. In an aquaponics system, plants take what they need and very little is squandered, and because nutrients are taken from the water rather than from soil, you don’t have to worry about traditional plant spacing. This means you can produce much more food per square meter.

So, for healthy food and a healthy environment, consider scaling up!

Paul Richards, Geomorphologist and Allister Logan, Aquaponics, Do it on the Roof

Talk to Allister today about aquaponic solutions for urban food production,


The Sunshine Donkey Orchid

It is 101 years since Martha, the last passenger pigeon died at a zoo in Cincinnati. Her stuffed body is currently on display at Smithsonian Museum of Natural History as part of a ‘Once there were millions’ display.

The once prolific Passenger Pigeon

The once prolific Passenger Pigeon

Before Europeans invaded North America passenger pigeons were one of the most plentiful birds on the planet numbering between 3 & 5 billion. They were a valuable but soon recklessly over-exploited commodity – a grim reminder of the ‘tragedy of the commons’. It is easy to dismiss this as an insular and dated tale but when we look around Melbourne 2 similar species leap into focus.

The growling grass frog once extended into the NSW tablelands and the ACT, but these populations were extirpated before 1981. At one time the species was so common in Victoria that the University of Melbourne used it as the dissection frog for their undergraduate courses and the Melbourne Zoo used it for captive snake food.

growling grass frog

The growling grass frog

Today the species is listed as endangered under the Fauna and Flora Guarantee Act Victoria (1988). Fittingly the species is the centre of a multi-institutional research program led by University of Melbourne researcher Geoffrey Heard.

A similar fate befell the beautiful and once common Sunshine donkey orchid (Diuris fragrantissima), which was also a commodity used in The University of Melbourne teaching practicals (Jones 1991).

Sunshine Donkey Orchid

Sunshine Donkey Orchid

Extensive utilisation of the basalt plains with the expansion of agriculture and Melbourne City has rapidly displaced the orchid so that the last wild population includes only about 40 individuals. Another collaborative research program is focussed on this species led by Arthur Rylah Institute researcher, Mike Duncan.

It is a relief that iconic species such as these have not been triaged out of existence because of ever diminishing finances. We should adulate companies and institutions that step into the breach left by political whimsy, and engage with conservation objectives, for extinctions portend the erosion of ecosystem services that will impact us all in the most profound ways.

Trevor Edwards, Ecologist

Jones 1991. Some rare or threatened Australian orchids. In, Conservation of rare and threatened plants in Australia. The proceedings of the conference: protective custody – ex situ plant conservation in Australasia. (eds. G. Butler, L. Meredith and M. Richardson). Australian National Botanic Gardens and Australian National Parks and Wildlife Service, Canberra.

Learning from Landscapes


Evolution of the Dandenongs

The Dandenongs are the remains of a long-extinct volcano. It was most active more than 350 million years ago, and it has been extinct since Australia was part of the Pangaea supercontinent. At its peak, this volcano was monstrous, and it is still the defining influence on the landscape of the Dandenongs.

The volcanic activity left behind hard rocks, which have endured. This includes lava-turned-rock (particularly dacites and rhyodacites), and molten rock that solidified before it reached the surface (particularly granodiorites). There are also some sedimentary rocks in the area, including sandstone.

Today, the landscape of the Dandenongs has an elevation of up to 633 m (at Mount Dandenong itself), and it is dissected by creeks. The result: a series of ridges and valleys with steep slopes, particularly in western sections like Ferntree Gully.

Water in the landscape

Water has been influential in shaping the Dandenongs, and the creek that dissected Ferntree Gully is still an important presence in the landscape. On the larger scale, this area is within the Dandenong catchment; rather than meeting up with the Yarra River, the rivers and creeks of this catchment make their own way down to Port Phillip.

Home on the Hillside

Within this unique landscape, on the edge of Ferntree Gully Park, sits Anton Englemeyer’s award winning home, at 8 Olivette Avenue. 

AE house

Fitting with the overall low environmental footprint of the home, 8 Olivette Avenue treads very lightly on the landscape, and helps to counter the effects of low-density urban development.The house begins filtering stormwater at the very top, on its green roof.AE roof

The substrate of the green roof immediately absorbs rainwater, some of which will be used by the plants and returned to the air, although most of the roof-captured rainwater is directed into two large rainwater tanks. By the time water has passed through the rest of the home’s 5-stage stormwater management system, there is much less of it. It is also cleaner than typical stormwater when it returns to the landscape, because sediments and nutrients (e.g. nitrogen) have been removed.

3- stormwater managment system main sediment pond

All of this makes for a better situation downslope, and beyond. Particularly given the absence of local storm drains. The slope itself is better protected from the erosive effects of stormwater (e.g. gullies), and properties downslope are better protected from damage too. 8 Olivette Avenue’s green infrastructure is also good news for Ferntree Gully creek, and probably for its big sister, Ferny Creek (these two creeks meet near Upper Ferntree Gully station).

These local waterways will benefit from receiving better-quality, lower-quantity runoff. For example, Ferntree Gully creek and Ferny Creek are home to a near-extinct crustacean, and stormwater drainage is the main threat to its existence. The mostly-indigenous plants grown on and around 8 Olivette Avenue also promote local biodiversity directly. Properties like 8 Olivette Avenue can even benefit the vast Port Phillip, particularly by reducing algal blooms caused by excess nutrients.

To find out more about this unique property, join us for an exclusive tour this Sunday 13 October for Sustainable House Day. Book your ticket today

Paul Richards, Geomorphologist

Urban landscapes, naturally.

green roof city hall

Geomorphology. The study of Earth’s form. Of landscapes and landforms and the processes that create them. It could be the most interesting field of science that you’ve never heard of.

Geomorphologists look at how the world’s landscapes are shaped by the actions of water, ice, wind, life, and geological processes such as volcanic eruptions. They study mountains, coasts, and deserts. No landscape is off limits. Some geomorphologists even study landscapes on other planets.There are urban geomorphologists too. They look at the interactions between landscape processes and urban development, and this is where geomorphology is relevant to green roofs.

As an example, imagine a pristine hillslope during a big storm. Much of the rain is being intercepted by the natural vegetation. The rain that makes it to the ground is seeping into the soil, although some of it is running over the surface, maybe in gullies. The flow of water in the creek at the bottom of the hill is slowly increasing, and sediment concentrations in the creek are changing. These are the types of processes that are studied by a geomorphologist, who will also look at the origin and evolution of the hillslope itself.

Now imagine the same hillslope covered in buildings and roads. It’s an entirely different story. When rain falls on this urbanized hillslope, it is almost certain to land on a hard surface, and it is likely to reach the creek very quickly. Even if the creek itself has escaped being modified as part of urban development, it will not escape the effects of its urban surroundings. It will change, and a geomorphologist would study this.

urban landscapes

And now imagine that every building on the urbanized hillslope has a green roof. The green roofs, by design, will capture rainwater that otherwise would have reached the creek. Urban development altered the processes of the landscape, but green roofs can help guide them back towards the natural state.

A geomorphologist can help to evaluate where green roofs are most beneficial, or how their design can be optimized. A geomorphologist can give green roofs context, by considering their place and role in the landscape. While geomorphology often overlaps with other fields, such as hydrology, a geomorphologist could see things that other green roof professionals might miss.

We are going to be thinking about how we can use geomorphology to create better green roofs and better cities. Because geomorphologists should Do it on the Roof too.

Paul Richards, Do it on the Roof

Melbourne’s war on leaves

Carlton gardens

Don’t you just hate leaves? They fall to the ground with their bad intentions, mocking us with their freedom to blow wherever they please and dirtying up our clean streets. Smug, crinkly jerks.

But what if our hate is misplaced? What if leaves are in fact, our friends?

If we look at the biological mechanisms that leaves are crucial for, maybe we can learn to appreciate them. After all, leaves play a crucial role in the health and vitality of our trees. You know—those things that pump out the oxygen we breathe. Trees shed their leaves (in a process known as tolerance) during winter in order to avoid damaging conditions.

But that’s only half of the battle…

The other half, as it turns out, is the part where the tree reinvigorates itself to come back stronger than ever. And guess what? It needs the leaves it shed during the winter in order to do that.

Plants need organic matter like we need water, nutrients and binge watching Netflix. The trees eat themselves via mineralised leaf compost in the soil. When we deny a tree of the natural process it creates for itself, we create nutrient poor soils and less healthy trees.

Too many times as an arborist and horticulturalist, people have asked that I remove a tree because it drops leaf litter and looks sick, not realising how crucial the leaf litter they remove is for the tree (as well as the surrounding ecosystem).


If we want our trees to be healthy, and we most certainly do, we must mimic their natural requirements as best as possible. This is difficult in an urban setting, sure—but by promoting awareness of the science of trees and the increasing importance of their protection and survival, I’m sure we can convince the world that leaves aren’t so bad.

How about this? The next time you’re about to ask your gardener to blow all your leaves down the street (or at the house of that neighbour who gives you the stink eye), pause for a moment. Consider that those leaves could be used for good, not evil, in our urban environments.

Compost them, mow them over and break them down the natural way, not in our drains and waterways.

Make use of the humble leaf, your trees and garden will thank you with vitality.

happy tree

Angus Murray, Horticulturalist – Do it on the Roof