With the population booming, there is a need for sustainable food models. What would it take to make widespread urban farming a reality in Australia?
Urban agriculture or ‘urban farming’ hasn’t really taken off either in Australia or around the world. The question is, why hasn’t the urban farming movement taken off and what can we do about it?
First things first: what’s it all about?
According to Urban Agriculture Australia, urban farming is the utilisation of local land and bio systems in order to meet the food needs of urban communities.
By growing what we need near where we live, we reduce the food miles associated with long-distance transportation, get the freshest produce money can buy, and reinvigorate the urban landscape. Plus, most green roof and wall systems are also highly water efficient and require less fertiliser.
Urban agriculture then, has the potential to address food security concerns, as well as improve community health and the urban environment. But can it produce enough food to sustain a city’s population? And is it worth the energy, resources, time and money needed to get the project up and running?
Let’s do some hypothesising.
How much food does one city need?
According to Urban Agriculture Australia, “It is estimated that a city of 10 million needs to import more than 6,000 tonnes of food daily.”
With a population of 10.23 million, London is a reasonably good size for this example.
So let’s pretend London needs 6,000 tonnes of food daily (we can assume the 0.23 million are visiting Australia for a holiday so we can work with a nice round number – thanks guys) and they want to source all this food through city-wide urban farming.
Finding the space
London has a 1,572 square kilometres of land area, so that means each square kilometre would need to produce 3.82 tonnes of food each day in order to hit the 6,000 tonne sweet spot. That’s daily consumption. And it assumes that every kilometre would be building-free and suitable for farming or animal husbandry. Now, we haven’t even thought of the people in the city – where would the 10 million be? Knee-deep in veggie patches? That seems unlikely and it would hardly be urban farming without buildings. In fact, that’s just transplanting a rural farm and that’s not what we’re going for, so let’s try again.
If we don’t have the space of a rural farm, we need to work with building tops and any unused area including vacant lots, parks and abandoned buildings. Basically, if it’s a reasonable space it has planting potential. Please note, my experience with rearing animals is limited to raising my kids so I won’t hypothesise on animal husbandry, grazing or anything like that. If it were up to my skill set, London would be forced to go vegetarian – sorry, London.
We would be taking the horizontal spread of a conventional farm and turning it on its head so everything goes up rather than out. Imagine a combination of vertical farms, rooftop gardens, shared community plots, terraces, balconies and so on. We’re using it all in some form or another.
Creating an optimal growing environment
Now we have the space requirements sorted (kind of) we need to ensure optimal growth conditions and harvest. It’s a tough ask to deliver 3.82 tonnes of food from 1,572 square kilometres each and every day. How can we get around it? This is where innovation and ingenuity come in.
We are asking for a crazy harvest volume and we haven’t considered the quality of the growing area, climatic conditions, the availability of natural resources, whether the soil is contaminated from its urban surrounds, crop rotation, and the list goes on. I can’t possibly address all these things here, but let’s pick out a couple of things and see what we come up with.
Soil contamination is pretty likely in an urban area. It’s especially likely in a big, old city like London. This is where the industrial revolution took off. It’s a place (like many established cities) where lead, mercury, arsenic, radium and asbestos were used a lot in building, plumbing, electrics and general odds and sods before we realised that was a terribly bad idea. So it’s reasonable to assume that a great deal of soil needs to be remediated or replaced before planting anything we intend to eat later.
Once the soil is clean and suitable for planting, we need to address two elements essential to all plant life – water and light. We’ve decided to maximise our harvest space with a mix of ground, rooftop and vertical planters. Ideally, each farm would research site limitations and choose suitable species for the conditions, reducing the need for increased energy and water use.
The modern city landscape however, presents a problem. So many skyscrapers means some gardens will be overshadowed by tall buildings and won’t get enough sun to grow. Vertical gardens with a stacked design also throw shade on their own produce – it’s one of the design concessions in order to maximise use of space. So we’ll need to install a sophisticated lighting system to provide our crops with the light they need. Add to that the need for water, so we’ll install a sprinkler system too.
These systems cost money, and the more crops we have, the more it will cost. So what we really need is technological innovation – a new and more efficient way to sustain our crops without using too much water or expending too much energy. We want something environmentally and economically sustainable so that we’re helping the planet rather than hurting it.
Urban farmers apply within
Now we have the space, soil, water and light needed to grow our crops we need one more thing – people to farm them. Soil won’t remediate itself just like produce won’t pick itself. We need workers to help us with these tasks.
One of the benefits attributed to urban farming is that it has the potential to revitalise depressed urban areas, boost the economy and create new jobs. With a massive London-wide project like this, there would certainly be a few more jobs around. I imagine the types of jobs at our hypothetical London farms would be wide and varied; there would be full-time, part-time and casual work available. There’d be roles for those with a green thumb, and roles for those who don’t.