Using a rooftop to host a garden which the building community cultivates in some kind of common space is an alluring notion. It seems an excellent means of meeting various planning requirements, achieving a high rating under WELL, and making use of an otherwise wasted space.

But does it work? Are community garden green roofs viable?

I believe the key factors which determine whether or not a community garden succeeds on a green roof are its operating budget and the way in which the roof’s manager conceives his or her role.

In the community garden model, maintenance appears to be “outsourced” to the community. Property developers, design professionals and above all, facility managers, generally expect that a base level of maintenance will still be required. In fact, in my experience, the need for base level maintenance by a facility manager is not inevitable. What is more or less invariable, however, is the need for more management.

It can be helpful to explore the case of a building community which cultivates a garden on a rooftop, the staff in the owner-occupied GMHBA office building in Geelong.

It is an inspirational case of a private company taking the initiative to green its roof for the good of both its own staff and the wider community. The crucial point it illustrates is that the type of management required is not simply the regular coordination of maintenance, but rather, the coordination of community engagement or educational activities.

Rooftop gardening on the GMHBA building

GMHBA is a health insurance and health services company which owns its head office building in central Geelong, just up the road from the waterfront. The three-storey building has a flat and easily accessible roof. Since February 2015, it has hosted a vegetable garden called the GMHBA Community Harvest. Paul Richards of Do it on the Roof visited the roof in April 2016 and spoke to Amy Gillett (GMHBA’s community manager) to help ensure all needs were being met.

The beginnings of Community Harvest

It all began last summer. The idea was to grow vegetables to donate to a local food relief agency, which provides hot meals to over 100 people, two nights a week.

The project is a great demonstration of how quickly and easily the first steps towards a complete green roof can be taken. After the executive manager brand & marketing became enthused about creating a rooftop garden, the project was given to the community manager who, with the help of more than 30 other GMHBA staff, installed the beds in a matter of weeks. The construction itself lasted a fortnight. The staff had little experience as gardeners but they made it work. That the company owned their building made it relatively easy to get things done. It also helped that weight was not a concern, because the building was designed to support additional storeys.

Maintaining the beds, and maintaining enthusiasm

There are 10 garden beds. Each of these is a container-style wicking bed with only one or two vegetable types planted in it. At the request of the food relief agency, the vegetables are now exclusively hearty types that can be cooked as part of a hot meal. So, currently, there are carrots, parsnips, capsicums, zucchinis, eggplants, silverbeet and Brussels sprouts.

The beds sit on besser blocks, at a convenient height for the gardeners – the GMHBA staff. Staff members were organized into eight teams of approximately 25 people each, including a team captain. Each team is charged with the responsibility of maintaining at least one bed. The team members are put on rosters, and work on the beds for up to an hour each week. Their tasks include hand-watering the beds using tap water. Taps have been installed close to the beds, and this easy access to water on the roof has been important. At one stage this was not going to happen, and it might have resulted in lower staff participation. The key point here is the importance of getting buy-in across the business.

Aside from helping disadvantaged members of the community, the GMHBA employees are also helping themselves. Their outdoor activities have been good for their health and tie in with the company’s staff well-being programs.

The team and roster system has been important in ensuring the employees stay engaged, and extra steps have been taken to keep enthusiasm high. This includes education sessions on how to garden, to enable staff to participate whatever their level of knowledge. A noticeboard on the rooftop window keeps staff updated, and there have been events such as rooftop barbecues.

All of this is possible because GMHBA never intended its initial installation to be final. With the intention to develop it came a budget for ongoing operations on the roof. They have also done things in a relatively inexpensive way.

Apart from more active employees, the company gets return from its investment in the form of various promotional opportunities, and the meaningful relationships with community organizations that have been cultivated.

So, are community garden green roofs viable? With an understanding of your building community and the type of management and maintenance needs that are likely to arise, a design which takes these into account, and a budget for ongoing community engagement or educational programs, yes, community gardens can work on green roofs.

The key thing to keep in mind is that the ongoing operational budget of these green roofs, often referred to simply as the maintenance budget, must provide for more than maintenance. It must provide resources to sustain the community’s interest and active involvement in the garden. This outcome is rarely achieved through a one-off expenditure, but approached with a sound strategy, costs can be confined and valuable outcomes achieved.