Published by City Farmer, Canada's Office of Urban Agriculture


An Urban Rooftop Integrated Microfarm For Mt.Gravatt's Commercial Buildings

The followinng paper was presented at the 3rd Mainstreet Conference in Melbourne on April 20, 1999.

How we can use vermiculture processing of local food wastes to create new businesses and new employment.

An Agrovision Publishing Report
Geoff Wilson,
Executive Officer (honorary),
The Urban Agriculture Network - Western Pacific Office,
PO Box 85, Mt Gravatt Central,
Queensland 4122, Australia.
Phone 61 7 3349 1422
Fax: 61 3343 8287
Mobile: 0412 622 779

Advancing technologies in Urban Agriculture (UA) represent new business opportunities for owners of commercial properties in shopping centres in Australia.

UA also represents new employment opportunities in CBDs and suburban locations, a particularly important objective in my view. Indeed, I believe rooftop farming projects now being developed in Brisbane and Melbourne, have the ability to create an entirely new vocation for the next century and beyond -- the vocation of "microfarming".

While King Nebuchadnezzar probably was the first to practice "microfarming" some 2,500 years ago when he ordered his architects and builders to create the famed Hanging Gardens of Babylon", it was based on very simple agricultural technologies of the time.

A large building was made to look like a mountain on the flat flood-plains where Bagdad is now located in Irak.

The building was aimed at making the king's wife less homesick for the mountains where she grew up.

But it put Babylon on the world map in terms of a wonderfully functional architectural creation.

According to archaeologists, the gardens on the rooftop were complemented by some remarkable cool storage for food in the vaults deep underground.

While the famed Hanging Gardens of Babylon were probably not motivated by anything more than a very rich man's whim, they were an amazing achievement.

Water was piped from the Euphrates river and lifted by hydraulic screws to the top of the wondrous stone "mountain", to cascade on irrigated terraces of lush food gardens in troughs of fertile river soil. It was an opulent use of riches that has never been repeated in the context of rooftop farming.

That will now change, in my view. We now have better, cheaper methods, and ways to make the concept create new businesses in our cities for new employment.

In the last 60 years of human endeavour, appropriate technologies have advanced light years ahead of what was in place in Biblical times.

Key technologies, such as hydroponics, aquaculture, aquaponics, vermiculture, and very small animal husbandry can now be integrated safely and economically into modern urban rooftop microfarms which can:

  1. Take food wastes from local restaurants and food shops.
  2. Put them through a biogas digester to eliminate pathogens and other harmful micro-organisms.
  3. Use advanced vermiculture to create nutrients for fish and plants from the sterilised food wastes.
  4. Grow fish, crustaceans, herbs, salad vegetables and selected small animals (such as quails and meat rabbits) for sale to local restaurants or food stores.

These technologies are now available "off-the-shelf", and have been well proved. What is different in the urban rooftop integrated microfarm concept I am developing, is the way the technologies are put together as a whole, to create new businesses opportunities and new employment.

They are also different in the advance that a group of us expect to make in meshing of modern hydroponics with ages-old production of plant nutrients from worm farming (vermiculture).

Additional financial and community benefits can be obtained if the rooftop microfarm also integrates:

Why consider a suburban rooftop area for the growing of food ? The question has a number of interlinked answers.

The first is that the world needs to develop local solutions to the chronic problem of organic wastes going to landfill. Of particular interest in Australia are food wastes in Australian cities. At present they go to landfill, where before they might have been used as pig food in a sensible recycling system. Most world cities still do this.

However, in Australia in the 1970s fears of spreading foot-and-mouth disease through recycling of food scraps via pigs, led to a national ban on this practice.

Since then, urban food wastes have been mostly going to landfill, leading to rising costs imposed on the creators of such waste, and the production of methane as the food wastes decompose. Methane is twice the greenhouse gas problem as carbon dioxide.

So, any recycling system that can tackle the food waste problem in our cities, and make it a successful business and employer, must be welcomed.

But why a commercial rooftop in a shopping strip? Why not a suburban block of land, as is used so successfully by an urban farmer in New Zealand?

The answer is that most commercial rooftops are under-used space readily available in urban areas. Land is not. In most inner suburbs of Australia it is difficult to buy land without a building on it, covered by restrictive residential use by-laws.

Another important point is that strip shopping centre rooftops are much closer to both the source of raw materials (food wastes from restaurants) and the market for the produce from the nutrient recycling via vermiculture (fish, herbs and salad vegetables for restaurant or cafe use).

Can such nutrient recycling compete with the existing system of supply of fresh food to our cities ?

A group of us propose to address this question. We are undertaking a wide-ranging feasibility study in Mt Gravatt Central.

Our ultimate aim is to develop an integrated rooftop demonstration microfarm to test ideas and to provide economic information for evaluation -- and the production of a set of manuals to guide innovative investors.

Of great relevance to our study is that fresh produce going into local supermarkets:

  1. Usually has about 40% to 45% of its retail price as transport cost. This has implications for governments aiming to reduce greenhouse gas and pollution emissions and transport energy fuel use.

  2. Usually has a least two days of shelf life lost from the time it is cut or picked, to the time it is goes out the supermarket checkout. Not so the produce from an urban microfarm on a commercial rooftop in a shopping centre. The time from harvest to sales counter can be half and hour or less. The world record so far is 10 minutes!

These two facts can be expected to mean competitive advantage to people investing in shopping centre rooftop microfarms in future. An employee wheeling fresh produce on a handcart to a restaurant a few hundred metres from the rooftop microfarm, can wheel back the restaurant's bagged food wastes for recycling!

In Mt Gravatt Central we are in the final stages of a Main Street Program part sponsored by the Queensland Government and by the Southside Chamber of Commerce.

We have a number of restaurants and cafes in our shopping precinct, and there is an ample number of hospitals, retirement homes and others with suitable food wastes. They also buy in significant quantities of fresh food (which lead to the wastes).

Sometimes this fresh food is transported 1,000 kilometres or more -- mostly because of a severe loss of peri-urban farms from the "urban sprawl" that has characterised much of the post-WW2 development around Australian cities.

This dependence of cities on distant farming now needs to be seriously questioned, in my view. At any one time, our city food stores contain a mere fortnight's supply.

Apart from the potential for seasonal disruption, or disruption from cataclysmic events, there are now the technologies available, such as hydroponics and aquaponics, to produce a great deal of fresh produce within metres of where is sold to consumers in suburban shopping strips and suburban malls.

Also, we now have the technology for continuous output of fresh food from urban farms, whereas the soil farmers are still dependent on rainfall or the availability of irrigation water, and the vagaries of seasons and pests and diseases.

Urban farms based on hydroponics use only a tenth of the water soil farmers require and many pests and diseases can be controlled with relative ease in urban locations. Urban farming means a massive drop in the use of pesticides, a point that will resonate with many city people concerned about their health and unexplained allergies.

But our feasibility study in Mt Gravatt Central is also aimed at:

Tied in with this are our aspirations for using our first rooftop demonstration microfarm as a training facility for investors interested in their own rooftop microfarms in other shopping centres, and for training operatives for these investors.

We also believe we will be creating a tourist attraction that will add to others we have identified through out Mt Gravatt Central Main Street Program.

This three year program, (which has cost the Department of State Development of the Queensland Government about $60,000, and local business about $120,000 in cash and kind), ends on June 30, 1999. It has also attracted around $1 million support from the Brisbane City Council, in streetscape development.

As a result, the Mt Gravatt Central Main Street Program has very effectively begun to turn around the fortunes of our local shopping strip in its competition with two mega-centres ( Garden City and Carindale) for shopping that are only kilometres away. It has begun to put Mt Gravatt Central back on the map in terms of consumer support of local retailers.

I believe our microfarm project will now put Mt Gravatt firmly on the world food map, and the world recycling map.

Both points will underpin our future development of businesses and employment if our feasibility study proves our belief in the potential of urban agriculture.

Copyright: Geoff Wilson, 1999. Not for publication without permission.

The feasibility study for the Urban Rooftop Integrated Microfarm is being undertaken by the Microfarm Association Inc. , under the auspices of the Southside Chamber of Commerce, using consultants with experience in urban agriculture, microfarming, small business management, marketing, urban planning, and fund-raising. The study grant of $20,250 was endorsed by the Brisbane South Area Consultative Committee for funding from the Federal Department of Employment Workplace Relations and Small Business. It is expected to be completed by June, 1999. The next objective, should the study prove the viability of the concept as both a profitable business, and a significant local employer, is to seek both government and private funding for a rooftop demonstration farm on a commercial building in Mt Gravatt Central.

Background on Geoff Wilson:
Freelance agribusiness journalist, Geoff Wilson, specialises in urban agriculture, microfarming, hydroponics, aquaculture, aquaponics and agroforestry . Geoff is also honorary executive officer of The Urban Agriculture Network (Western Pacific) -- a world-wide network of 6,000 professionals aiming to improve urban food production, especially from recycling organic wastes. Geoff has written for most rural newspapers and magazines in Australia over a 42-year career since graduating from agricultural college. For 10 years he was agribusiness columnist for "The Age" newspaper in Melbourne, and was managing editor of technical magazines in food and forestry. Geoff is currently Hon. Secretary of the Mt Gravatt Central Main Street Committee. As President of the Microfarm Association Inc., he is involved in planning for an "Urban Integrated Rooftop Microfarm" in Mt Gravatt Central.

The future importance of recycling organic wastes from urban areas is highlighted by the expansion predicted for world-wide urbanisation. The world currently has a population that is about 45% urban. The United Nations has predicted that, within a generation, the world's population will be more than 80% urban. This has implications for world food security -- made more serious by what is currently happening in degradation of agricultural land, the pollution of water resources, over-fishing of seas, lakes and rivers, and the twin problems of climate change and depletion of the ozone layer. These worrying background events in our current lives underline the importance of innovations such as the urban rooftop integrated microfarm

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Revised Friday, February 11, 2000

Published by City Farmer
Canada's Office of Urban Agriculture