Monday, August 23, 2010

How To Compost, Reduce Food Waste & Save The World

As I've slowly learned the basics of growing food at home, I've become increasingly impassioned by the origins of my food and the process that it undergoes to reach the dinner table; however It wasn't until I transformed my front yard from a muddy bank into a tiny but thriving vegetable patch that I gave any thought to the path that food takes when it leaves the kitchen.

Since the 1950's when large scale supermarkets and centralised food production became the norm, we've lost some of what was once considered common knowledge. Nowadays you rarely see people tending to their vegetable garden out in the suburbs or picking edible wild 'weeds' by the roadside. My sister practically lives on dehydrated 2-minute noodles loaded with MSG; the girl next door can't eat anything with a recognisable face; a little boy who lives across the road believes that everything he needs to live a healthy life resides in a packet of crinkle-cut chips.  

As a society we're spoiled rotten and our ethos has turned largely to materialism so it's no wonder that we're becoming increasingly detached from the origins of the very lifeblood of which sustains us. We've ceased to think of food as food should be. It's just another product that comes from only God knows where.

Food and paper, if left to nature, both decompose and return nutrients to the earth. It's terribly ironic then that food waste is the #1 least recycled material and it's absolutely horrendous to think that these two components combined, contribute to nearly 50% of all municipal solid waste. When buried in landfill, they're deprived of oxygen and begin the long process of anaerobic decomposition. This produces methane: a greenhouse gas, 21 times more potent than carbon dioxide. Food waste in landfill also results in something called leachate - a toxic chemical runoff which seeps deep into the earth to enter our drinking water.

Dumping food in landfill not only contributes to polluting our environment, but also detracts from precious nutrients that should be returned to the earth. Farmers are forced to use chemical fertilisers to replenish nutrients in the soil year after year, which itself poses a cataclysmic kaleidoscope of problems.

If you have a garden and even if you don't, there is something you can do. Reduce the amount of methane-producing waste you send off to join the millions of tons of compacted waste already in landfill. You can do this by composting your food scraps, plant debris, charcoal, paper, cardboard, toilet rolls, coffee grounds, even hair. Newspapers can be composted too since printing ink is soy-based nowadays. If in doubt, anything derived from something that was once living can be composted. In Sydney, 52% of the average household bin is compostable material. Some councils offer cheaper rates for rubbish disposal if you ask for a smaller garbage bin which could potentially be a huge money saver.

There are a few different options when it comes to compost.

The cheapest option (if you have a garden) is to mound up your scraps with grass clippings and dried leaves in one big pile. Thermophilic micro-organisms will heat up the pile and if you give it a mix (for aeration) once every week, in about 2 months you'll be left with a lovely rich compost. The heat produced with this method will effectively kill bacteria and weed seeds.

A compost tumbler is a fancy barrel fixed to a pivot that can be filled with material and aerated by spinning. It composts quickly but without reaching high temperatures.

Keeping a worm farm is a little more compact and neighbour friendly if you don't have a large garden space. All you have to do it place some moist coir (fibre from coconut shells) into the bottom, put a box of composting worms inside, give them some food scraps, a sprinkling of soil and a moist layer of newspaper over the top. Keep them out of the sun and rain. They'll eat their weight in scraps a day and any liquid produced can be diluted with 10 parts water and used to fertilise the veg.

The Bokashi Bucket is a relatively new system. Its design allows you to compost meat and fish which are usually avoided so as not to attract rodents or vermin. The bucket is able to be kept indoors or under the kitchen sink; the micro-organisms work anaerobically and the sawdust/bran mix sprinkled on top acts to absorb any unpleasant smells which may occur from the decomposing matter.

There is one more option that in my mind, is also the most efficient for home users: 
"NatureMill brings home composting to the mainstream user. It is essentially a miniature in-vessel kitchen composting system. NatureMill delivers an answer to the problem of space and labor for both traditional composting.. Waste is collected right where it is generated—in the kitchen. A computer controls the temperature, air flow, moisture, and mixing to accelerate the process and eliminate the backbreaking work. Everything is fully self contained in a modern, attractive container. Just a few square feet of floor space is required. No special plumbing or electrical connections are needed, other than a standard electrical outlet.. Best of all, NatureMill provides home gardeners with a source of rich, organic compost. And there is something uniquely satisfying about witnessing the entire food chain: from the garden, to the dining table, and back to the garden again.

All of these systems work by employing either worms or micro-organisms or both, to turn carbon and nitrogen-rich waste into beautiful, dark compost that can be added back to the garden. The benefits of composting are many. Not only does it act as a fertiliser, but the addition of organic matter also improves soil structure which enhances moisture and nutrient retention, increasing microbial activity.

Composting eliminates methane production in landfill but digging compost into the garden goes further through a process called carbon sequestration - atmospheric carbon dioxide is trapped in organic matter and buried. All plants need carbon and with a more readily available source for them to tap into, they'll have more energy to grow.

Scientists are looking to sequester carbon to counter global warming on an industrial scale in the future but we don't have to wait for years to make a difference. Do your bit by simple composting and help save the world, at home.


  1. I agree. It seems like so much of what we send to landfill can be composted.

  2. Where I work at a major sporting stadium, to help with our green rating we have started a green waste program. We can now recylcle 100's of kilos of uneaten food that has to tossed. When food has been out on a buffet, or in a bain marie, we can't pass it on to someone like Oz Harvest, and there is only so much I can get my dog to eat! I see this as a major acheivement even if management are doing so for tax/carbon credits instead of ethical/ecological concerns.
    Thanks for stopping by my blog and the tip about sorbet!

  3. I can't wait for the day when everyone learns how to make their own compost. If only we were as forward thinking as cities like San Francisco where composting is mandatory for all residents!


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