Wednesday, June 16, 2010

DIY food

This post is not really about how to grow your own food. There are plenty of excellent websites giving that sort of information.

Rather, it is about the reasons for DIY food. Of course there are many reasons - the freshness and the intense bursting-with-life flavour of home-grown produce, the avoidance of chemicals (if one chooses), and some sort of basic satisfaction or sense of achievement. Some might say DIY food saves you money, but I doubt if that is really the case, especially in the short term. It certainly is not true if you put a dollar value on your time...but there are other values.

In "Growing food in our cities" (p2, Best Garden Ideas - Growing edibles, published by The Diggers Club), Clive Blazey presents some compelling reasons for DIY food.
Nearly 30% of the CO2 in our atmosphere is caused by us not growing our own food.
Non-renewable energy is used to plough the fields, harvest and process the crop and take it to market. The fertilisers, pesticides and weed killers used to grow the crop are derived from oil. ... The kitchen fridge uses more energy than the farm tractor. ... Up to 25% of the energy is consumed in wasteful packaging. 
If this [growing our own food using compost rather than fertilisers] sounds like Utopia it is, and we have been there, before the supermarkets manipulated our lazy nature.

Blazey then tells how Cubans, who formerly relied on imported oil, tractors and fertilisers, have been growing their own food on disused building sites since the 1990's. These days "the city of Havana produces 60% of its own food" and "80% of the nation's food is organically grown". 

Whenever I read yet another article about the current and potentially increasing food security problems being caused by climate change, I can't help remembering something I read many years ago about the breakdown of the old Soviet Union. The author (Solzhenitsyn, I think it was) said that the hardships caused by disruption of mass food provision and distribution systems would have been much more dire were it not for the fact that many Russians were still in the habit of growing at least some of their own food in their own gardens. He wondered how well the average American (and presumably anyone else who relies entirely on supermarkets for their food) would survive under similar circumstances. For me, this is yet another compelling reason for pursuing DIY food.

I currently fall far short of food self-sufficiency. However, I am accumulating experience and knowledge about how to grow food - there's so much to learn! - and about what works well and gives good yields in my local area. Maybe this knowledge, and the seeds I am saving, will some day assist others who want/need to grow their own food as well.

I wonder how many people assume (without realizing that it is an assumption) that our supermarkets are obliged to keep us fed (they're not!), and to do so at "affordable" prices? achievable is DIY food?

To quote from Clive Blazey again (p14, Best Garden Ideas - Growing edibles), "In just 40 square metres you can grow 472kg of vegetables [per annum] which is enough for four people". (His planting plan is available online at .) To do that he says you will need plenty of sun and well-rotted manure, and also compost and blood and bone. You'll need to practice crop rotation, sow high-yielding heirloom varieties, and provide 22,800L of supplementary water per year. (I think you'd also need to do some preserving of the summer bounty to supplement the few types of vegetables harvestable during winter.)

I understand Blazey conducted the trials on which his yield figures are based at Seymour, 98km north of Melbourne, which has a mean annual rainfall of 593.9 mm. Comparing this with average rainfalls in your particular area will give you an idea how much supplementary water you would need. (For rainfalls within Australia, go to Climate Data Online and select Rainfall - Monthly - your location.) For example, Sydney's mean annual rainfall of 1129.6mm is almost double that of Seymour, Perth is also higher at 738.6mm, but the Adelaide figure is only 542.6 mm. So, by rough guesstimate, the supplementary water requirement in Sydney would be around 12,000L, in Perth it would be around 16,000L, and in Adelaide up to 25,000L of additional water would be required to grow those 472kg of vegetables. Even this worst case is quite achievable - one of my rainwater tanks holds almost that much.

A family of four having 3 minute showers with a water-saving shower head would generate 4 x 30 x 7 = 840L of greywater per week. Assuming slightly longer showers when washing hair, etc., we can probably assume at least 1,000L per week. (Click on the tabs at the top of the page, or start with this page, for collection and distribution methods). Given the wet winters and dry summers expereinced in much of southern Australia, we might need to water our gardens during only 26 weeks of the year, and so we'd only collect the used shower water during those weeks. That would mean a ballpark figure of 26,000L of greywater from the shower per year. That is enough, even in Adelaide!

One complication with the above greywater figures is the health guidelines for safe use of greywater, which indicate that greywater should not come in direct contact with food that will be eaten raw. Even so, lettuce, carrots, spring onions, and other salad vegetables that touch the ground could be in a separate bed that is watered with rainwater or mains water, and the shower water could be used for the other vegetable beds and for some fruit trees.

Despite being very approximate, the above figures indicate that a lot is possible, even for those who might not have quite the expertise, space, or soil fertility to match the above yields. Even a few pots on the patio containing, for example, a tomato bush, a climbing cucumber plant, a few loose leaf lettuces and some strawberries will avoid some of the food miles, packaging, etc. involved in supermarket food.


Food swaps (SA) (Vic) (Vic) (Vic) (scroll down for national list)

Blazey's 40 square metre planting plan . (I've not personally tried this planting plan, so I'd be interested in comments from anyone who has.)

Mean annual rainfalls
Climate Data Online. Select Rainfall, then Monthly, then enter your location. Look under the "Annual" column in the "Mean rainfall" row of the table.

Preserving the harvest

Growing food
Sustainable Gardening Australia

Buying local - next best thing to growing your own

Community gardens

Farmers markets directory

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