GardenDrumIs urban food security really possible?

Growing vegetables at homeIs urban food security possible if we all grow our own food at home? No, it’s definitely not.

Many supporters of the grow-your-own-food-at-home movement claim that doing so can improve a city’s food security, with less reliance on external food sources needed to sustain its population. It sounds plausible, and the idea feels good but a US study showed that it just can’t be done. Even if you remove all your urban trees.

Researchers at Seattle’s Washington University School of Environmental and Forest Sciences used modelling to assess the output of Seattle’s urban farms against what is required to sustain its population. Inputs to the model included the mix of food crops necessary to maintain a year-round nutritious vegetarian diet, realistic land use scenarios where all possible land was devoted to crop growing (including home gardens, all public land, vacant lots and rooftops), soil types and availability of water and nutrients, suitable crop growing temperatures, and the effect of tree shading on land productivity.

Brussels sproutsWhile acknowledging that each city has its own unique MFCPC, Richardson and Moskal reported in the Elsevier journal of Urban Forestry and Urban Greening that, at Maximum Food Crop Production Capacity (MFCPC), only 1% – 4% of Seattle’s needs could be met by urban farming and that this reduces by around 20% if the existing tree canopy is retained.

The model found that to meet 100% of its food needs, Seattle would require a 58km radius food production belt.

So while you might enjoy growing food at home, and it may be more delicious and even nutritious, it’s not going to improve the food security of your city or town.

Leafy crops to grow at home

Journal: Urban Forestry & Urban Greening – Volume 15, 2016, Pages 58–64

 

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2 thoughts on “Is urban food security really possible?

  1. archlea on said:

    The claim is that urban food production increases food security, which is indeed true. As it is, many countries have cities that produce over 50% of their own food in urban production (Ghana, China, Cuba etc.). It’s not that it can’t be done, it’s that the will to do it in already developed (and generally well-supplied) cities has not been there.

    It’s true that cities such as San Francisco and New York would be unable to grow enough food within city limits to feed the population- but not true that it wouldn’t contribute to food security. Non-traditional methods such as roof top gardens and vertical gardens are also being utilised to increase growing space.

    Food security is about access to food – whether bought or grown- and growing your own is often more economical, as well as more environmentally sound. Bonus! Some countries already have urban food production built into city planning.

    We need to loacalise production more generally, including food production. Areas for food production would ideally be part of any urban expansion plan. London has clearly demarcated city boundaries, which preserves surrounding agricultural lands – while Melbourne, Australia, has ever-changing urban planning boundaries that allow valuable farm land to be eaten up by suburban sprawl. And then new occupants complain about the noise of neighbouring farms! With less than 3% of the worlds surface ideal for crops (and approx 10% arable according to World Bank) it’s time we get smart about our survival!

    • Unfortunately people in most developed countries see year-round access to a very wide variety of top-quality fresh fruit and vegetables (whether they’re in season or not) as their right and they also end up throwing away a large percentage of what they buy. This means that locally-grown food production can never match demand and it would take a huge shift in culture and thinking – to the way people in Ghana, China and Cuba think of their food as a precious local resource – for the two to have any hope of coming together.

      I can’t agree that growing your own food is either more economical or environmentally sound than the specialised production of well-managed commercial market gardening. Growing food well in an urban environment requires a lot more inputs than people think, or take into their calculations. Even doing it ‘organically’ without petro-chemical derived fertilisers means buying in bags soil improvers, usually manures sourced from intensive chicken sheds and feedlot cattle (not environmentally friendly in my view), plus the use of copious amounts of precious potable water. And so many home vegie gardeners turn to chemical intervention when they see their crop destroyed by pests, big and small! Truly sustainable home growing would mean a closed loop system of no offsite inputs or outputs, including water and fertiliser. In 25 years I’ve only seen one home gardener growing both plants and animals for food on several acres and with over 60K litres of watertanks come close to that.

      However I do agree wholeheartedly with you about the terrible shortsightedness of our government planners who think it’s OK to develop good quality peri-urban farmland previously used for intensive market gardening and instead to truck in fresh vegetables from hundreds of kilometres away. So stupid.

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