Food grows everywhere, that's not really the problem. The problem is the convoluted system we have for picking and eating it. Jean-Jaques Rousseau wrote:

"The first man who, having enclosed a piece of land, bethought himself of saying `this is mine' and found people simple enough to believe him, was the real founder of civic society. From how many crimes,wars and murders ... might not any one have saved mankind, by pulling up the stakes or filling in the ditch, and crying to his fellows: `beware of listening to this impostor!'? You are undone if you once forget that the fruits of the earth belong to us all, and the earth itself to nobody."

As things stand, I could not get up and walk out of the city and survive. this is because all the land "belongs" to someone. Some brave people do try to live like this. They are called travellers and sent to prison. The reason they are travellers is that they aren't allowed to stay anywhere. Wherever they go the locals, in their smug suburban self - satisfaction, won't tolerate them and have the nerve to call them dirty, while their own sewage kills the rivers and their rubbish festers in giant landfills or burns in incinerators, poisoning the ground water and the air... But their gardens are nice and tidy aren't they?

All the food we eat comes originally from wild species. I stayed on a farm for a while once, which kept cattle. One day I saw the farmer running across a field banging two pans above his head. When I asked why, he said he was chasing some deer away. As I persevered with my questioning he said that the wild deer ate a lot of grass which was for his cattle. I asked why he didn't just forget about the cattle and eat deer meat instead, as this would obviously make for an easier life. He mumbled something about city folks and stormed off. Of course I'm not really that stupid - I know about mortgages and such like. Mortgage actually means `death grip' in French. Perhaps if more farmers could speak French they wouldn't have got in the mechanised mess they are in now."