The morning I finally decided to give up using cash, the whole world changed. It was the same day news broke about the banks' misbehaviour in the sub-prime mortgage market, so when I began telling people of my plans, they assumed it was in preparation for some sort of apocalyptic financial meltdown. However, having long viewed credit as a debit against future generations, I was infinitely more worried about what George Monbiot called the "nature crunch". Nature, unfortunately, doesn't do bailouts.

I suppose the seeds of my decision to give up money – not just cash but any form of monetary credit – were sown seven years ago, in my final semester of a business and economics degree in Ireland, when I stumbled upon a DVD about Gandhi. He said we should "be the change we want to see in the world". Trouble was, I hadn't the faintest idea what change I wanted to be back then. I spent the next five years managing organic food companies, but by 2007, I realised that even "ethical business" would never be quite enough. The organic food industry, while a massive stepping stone to more ecological living, was rife with some of the same environmental flaws as the conventional system it was trying to usurp – excess plastic packaging, massive food miles, big businesses buying up little ones.

My eureka moment came during an afternoon's philosophising with a mate. We were chatting about global issues such as sweatshops, environmental destruction, factory farms, animal testing labs, wars over resources, when I realised I was looking at the world the wrong way – like a western doctor looks at a patient, focusing on symptoms more than root causes. Instead, I decided to attempt what I awkwardly term "social homeopathy".

I believe the key reason for so many problems in the world today is the fact we no longer have to see directly the repercussions of our actions. The degrees of separation between the consumer and the consumed have increased so much that people are completely unaware of the levels of destruction and suffering involved in the production of the food and other "stuff" we buy. The tool that has enabled this disconnection is money.

If we grew our own food, we wouldn't waste a third of it as we do today. If we made our own tables and chairs, we wouldn't throw them out the moment we changed the interior decor. If we had to clean our own drinking water, we wouldn't waste it so freely.

As long as money exists, these symptoms will surely persist. So I decided, last November, to give it up, for one year initially, and reconnect directly with the things I use and consume.

The first step in the process was to find a form of sustainable shelter. For this I turned to the amazing project Freecycle, through which I located a caravan that someone else didn't want any more. I also needed somewhere to put this new home, so I decided to volunteer three days a week at an organic farm near Bristol in return for a place to park my caravan. Had I equated this in terms of my previous salary, it would be like paying penthouse apartment rent for what was effectively a little tin box. But that was the type of thinking I was now trying to get away from.

Having no means of paying bills, the next challenge was to set this home up to be off-grid. For heating I installed a wood-burner I'd converted from an old gas bottle, using a flue pipe I had salvaged from the skip. I fuelled it using wood from trees we coppiced on the farm, meaning fuel miles became fuel metres.

A local member of the Freeconomy Community (the alternative economy which I founded in 2007), then showed me how to make a "rocket stove" from a couple of old olive oil catering tins that were destined for landfill. This meant that for the next 12 months, I was going to have to cook outside. I was a touch overwhelmed by the thought of cooking in the snow, rain and northerly winds of a British winter. But, surprisingly, it has become one of the joys of my life.

While feeding the stove with broken-up old vegetable boxes, I would watch the moon rise in winter and the sun set in summer for the time it took to prepare my evening's repast. Birds in the trees around my kitchen became my new iPod, and observing wildlife taught me much more about nature than any documentary I'd seen on the television.

The one thing I did spend money on (about £360) before beginning the experiment was a solar panel to supply me with enough electricity for a light, my laptop and my phone (on which I could only receive calls). Solar isn't ideal because of the embodied energy involved, but at the start of what might be a lifelong journey, I couldn't expect everything to be perfect straightaway. And the solar panel has always provided me with light – although in winter my phone and laptop time were severely restricted (frustrating, but only because my expectations were based on having infinite energy at the touch of a button).

The last piece of my off-grid puzzle was a compost toilet. This should really be the symbol of the entire sustainably living movement, in the way the spinning wheel became a symbol of Swadeshi in India. Representing sanity and a respect for the earth, I made my alternative loo out of old pallets from a nearby hardware store. As I can no longer buy toilet roll, I relieve the local Bristol newsagents of some of the newspapers that fill their bins every day, and use them instead. It's not double-quilted but it quickly seems normal, and I even used a story about myself once . . .

I wash in a river or under a solar shower (better in the summer), and rarely use soap, but if I do I go for home-grown soapwort. For toothpaste I use a mixture of cuttlefish bone, which gets washed up on the UK's shores, and wild fennel seeds.

Food was my only other real necessity: I think of there being four legs to the food-for-free "table". Growing your own, which is obviously what I've been doing here on the organic farm (my staples are potatoes, beans, kale, carrots, salads, root vegetables, squash, onions and swede); wild food foraging, which is nutritionally exceptional and beautifully gentle on the environment (I forage for berries, nettles, mushrooms, nuts and greater plantain for a hayfever remedy); and also securing waste food and other goods from local restaurants and shops. This is an incredible resource to draw on, and although its existence is, of course, dependent on industrialised society, I feel like I have an obligation to consume it before using up any more energy producing food.

In fact I'm currently organising a free mini-festival called the Freeconomy Feast 2009, where myself and Fergus Drennan, the BBC's Roadkill Chef, aim to feed 250 people a three-course meal with full service for free, completely out of waste food and things foraged from the wilds of Bristol. It even includes free beer made from locally grown and foraged ingredients.

The final leg of my food table is bartering – using my skills or any excess food I've produced to secure anything not met by the other three methods. This means I meet people from all walks of life doing what I do, and while many claim that they couldn't – or wouldn't want to – do the same, most seem to understand where I am coming from and resolve to reduce their own consumption wherever they can. When I first said I was going to do this, my parents probably wondered what they should have done differently during my formative years, but now they are right behind it, and may even contemplate joining me one day.

But what I soon realised is that, in a moneyless world, everything takes much more time. Handwashing my clothes in a sink of cold water, using laundry liquid made by boiling up some nuts on my rocket stove, can take two hours, instead of 10 minutes using a washing machine. Finding stuff in skips – such as the steamer I cook with – takes far longer than popping out to the shops for one, and sorting out the compost toilet is a lot more hassle than flushing it "away".

Cycling the 36-mile round-trip to Bristol also takes a lot more time and energy than driving or catching the bus or train, but it's also an economical alternative to my old gym subscription, and I find cycling much more enjoyable than using motorised vehicles.

The point is, I'd much rather have my time consumed making my own bread outdoors than kill it watching some reality TV show in a so-called "living" room. Where money once provided me with my primary sense of security, I now find it in friends and the local community. Some of my closest mates are people I only met because I had to build real relationships with others based on trust and kindness, not money.