The way to know most about the vegetables you cook and eat is, of course, to grow them yourself. In all honesty, I am hardly a leading authority on the art of growing vegetables (though by plundering the knowledge of others and reading the back of a few seed packets I have attained a level of competence that serves me well). Nevertheless, I am an unremitting, if recently converted, enthusiast, and I have probably given more thought than most to the question, 'Why bother?' So what can I say to the enthusiastic cook who is vaguely interested in the idea of growing his or her own vegetables but is still teetering on the brink of action? Realistically, for most of us these days there are no persuasive economic arguments for growing your own vegetables - at least, not if you cost out your time. (During summer gluts, my father used to pay me pocket money to pick and freeze peas, beans and soft fruits from his vegetable garden. He once calculated that the resulting frozen produce cost him three or four times what it would in the supermarket. And that was without factoring in his own time).

But there is still an important sense in which the vegetables you grow yourself really are free. When your time is given freely, what you make with it is free in the best sense of the word. When you buy your vegetables, you are a slave - to the car that takes you to the shops; to the methods, good or bad, by which the vegetables are produced; to market forces, and the big bosses who fix the prices; to the shelf-stacking policies that determine the freshness, or otherwise, of the produce you buy. You have no say whatsoever in the means of production, no role in the quality of what becomes yours only when you hand over the cash.

Grow your own vegetables and all that changes. Choose the seeds, the growing site, the time to plant, to weed, to water, to feed, to harvest. What you then take to the kitchen is not just a vegetable. It's a form of self-expression, an assertion of personal liberty. It's a kind of opting out of the world as you're told it must be in favour of the world as you'd like it to be. You may doubt the wisdom of loading something as ordinary as a carrot with such deep personal meaning. But try growing them yourself and you will find that carrots are far from ordinary. They are sleek, pointed orange miracles that come from nowhere to populate a bare patch of earth. And, almost astonishingly, you can eat them! The fact is, those who already grow their own vegetables for the kitchen need no converting to the cause. I have yet to meet a vegetable gardener who complained that 'It's hardly worth it, what with the choice available in the supermarket these days', or 'It's too much time for too little reward, or 'What's the point, you can hardly taste the difference anyway?' These quotations are the clichés of the uninitiated - those who do not yet know the prickly heat of a fat radish, freshly drawn from the earth, washed with a wipe on a dewy tuft of grass, and eaten without further ado; those who have not tasted the extra sugar dose in a pile of self-podded peas plunged into boiling water within an hour of being picked; those who have not marvelled at the unrepentant earthiness of freshly dug potatoes...

If you are still wavering, let me offer you another, almost glib, answer to the question, 'Why grow vegetables?' Because you can. I mean, anyone can. Growing vegetables is easy: all you need is earth and seeds. Sunshine and water are important too, but in a reasonable year both should come in plentiful supply, courtesy of the man upstairs. A relaxed, laissez-faire attitude to growing vegetables will stand the beginner in good stead. While there is plenty of scope for fussing and fretting about your vegetable patch, you will probably find that obsessive attention to detail either does or doesn't evolve as the years go by, according to your personality. In other words, if you want to become the manic overseer of a manicured vegetable plot, you can; but it doesn't have to start off that way.