People are increasingly realising that what they eat is important. You can't put junk food in your body and be healthy. All sorts of problems can develop, like diabetes, heart disease, obesity, strokes. Gardening not only helps with exercise and mental health, but it can improve diet as well.

When you plant something, you invest in a beautiful future amidst a stressful, chaotic and, at times, downright appalling world.

There is a direct correlation between gardening and mental health, not just to maintain good mental health but to repair it as well - that's anything in the gamut from depression to serious brain damage, schizophrenia or autism.

Once you engage with the simple enough business of feeding yourself, of soil and water, weather, season and harvest, it becomes personal. It is about you, your family and friends. Food becomes an aspect of those relationships as well as your intimacy with your plot.

I use the period between Christmas and New Year to potter about, think and completely change my mindset. In that easy no-man's-land between Boxing Day and New Year, loins are girded and mettle readied. It is time, as we voyagers bid farewell to the old year, to fare forward.

Absorbing a healthy amount of dirt builds your immune system.

I think that the essence of a Christmas wreath - of all Christmas vegetative decoration - has to be green and, if possible, living. So the basis of a wreath is ideally holly, laurel, ivy, rosemary, larch, fir or whatever is to hand.

Organic is loaded with a sense of rightness, with a set of rules. I would much rather someone bought food that was local and sustainable but not organic than bought organic food that had to be shipped across the world.

Woods are rich with biodiversity and, above all, places of trees and light that spangles a thousand greens through the leaves.

That first snowdrop, the flowering of the rose you pruned, a lettuce you grew from seed, the robin singing just for you. These are smallthings but all positive, all healing in a way that medicine tries to mimic.

I always see gardening as escape, as peace really. If you are angry or troubled, nothing provides the same solace as nurturing the soil.

Happiness is a by-product rather than an end in itself. It pops into your life unbidden, and then tends to pop out again. I'm on record as being depressive. It is related to winter.

If I'm honest, the thing I am proudest of is my varieties of wild flowers in the hay meadow.

We are extremely uncomfortable with the spiritual aspects of gardening, and yet most people feel it in some form or other, even if it's a sense of connection to the greater world on a beautiful day.

For every gardener there is a minimum level of engagement that is needed to sustain and develop the relationship. There is no magic figure to this and it will vary from person to person and season to season, but it is there.

Gardening is easy. Stick it in the ground the right way up and most plants will grow perfectly well.

Daffodils, blossom and tulips jostle to the front of the stage in April. I love these early perennials: they may be more modest but they nearly all have that one special quality that a plant needs to transform your affections from admiration to affection - charm.

I was a sickly child, and it wasn't until I was 19 that I realised I was quite a robust, vigorous person. Since then I've taken ill health to be an irritating interruption into what is a fairly reliable stream of good health.

I'm a great believer in trying things, so I've eaten witchetty grubs, a mountain frog, ostrich and alligator. I like tongue, I like brains and tripe.

Sweet peas should smell. Half the point of growing sweet peas is to cut them for the house; they should fill a room with an almost painful olfactory inarticulateness. But most sweet peas smell of nothing. This does not stop them being beautiful, but they are like food with no flavour.

A plant I have grown for years without really taking much notice of is epimedium. You know how it is: someone gives you a plant, you stick it in the ground and somehow it never presses the trigger. There is no intimacy.

Apples hate strong wind and damp, cold soil so try and place them on well-drained, rich soil in a sheltered position.

We undervalue food in this country, yet Britain has beautiful food and beautiful growing conditions. It is astonishing the range we can grow.

My father was an army officer who left the forces when I was six and never really fitted back into civilian life. My mother had five children and a mother with Alzheimer's, who lived with us, so I imagined that she had a lot to do.

Any British household with a scrap of land has always grown herbs for the kitchen. From the superb monastic herb gardens down to the humblest cottage, a supply of fresh herbs would have been considered essential.

Trees are complicated, fascinating things, usually older and more beautiful than any of us.

You can trace the entire history of Britain by looking at gardens.

Plant breeding has been going on for millennia and it's a gradual process.

I wouldn't want to be known as Mr Depression, but I found that when I did dip a toe in the water and talk about it, the response from the public was incredible.

The more people share woodland, absorb it and regard it as part of their personal heritage and culture, the richer our society will be. The more people can work in woods and use them practically rather than go through the motions as a kind of ersatz exercise, the more they will care for the places themselves rather than the political idea of them.

I'm bad at sleeping. I get somewhere between three and six hours a night.

The divide between a 'wild' plant and what is suitable for the garden is unnatural and meaningless. Gardens begin and end in the mind, and the Western way of thinking is not good at accommodating that.

I have been growing vegetables since I was a boy. When I was about 17 I was the only one of five children living at home. My parents were ill and I took over the vegetable garden and I have had one ever since.

Gardening is seen as a pastime that is almost like belonging to the Church of England - a sign of maturity and wisdom and right thinking.

I am always more interested in people than plants. Nature doesn't make gardens, people make gardens. And the story of a garden is always the story of a person.

I love filming. I love the teamwork. It's a tight-knit group spending months on the road together. All the experience is shared.

I have always felt that the best gardens aspired to coppice and that the best woods have all the elements of the very best gardens.

I have learnt that gardens are like happiness: you cannot pursue them as an absolute thing or moment.

The British have such an odd relationship with food - and the land. I want the public and the Soil Association to see that growing things in a garden is no different to growing things in a field.

As September rolls into October, I become obsessed with apples. Now obviously this is provoked by the ripening fruit clustering on the trees in our orchard, but it is as though all things pomological ripen in me, too.

A healthy plant is one that adapts best to the situation in which it finds itself. There is no objective measure of this.

You would be surprised at how many letters I get criticising me for straying outside the strict limitations of horticulture or even for expressing what is clearly an opinion.

Ground elder, introduced by the Romans as a vegetable, is difficult to get rid of because it regrows from the smallest trace of root.

I think that most people are aware that it takes so much oil and water to produce what they're eating. But the problem is inherent within the solution, in so much as you don't want to tell people what to do.

Many gardens are hijacked by their plants and end up looking like a room overstuffed with furniture.

No apple is reliably self-fertile, so each tree needs a pollinator. A neighbour may well have an apple that will do that for you, but it is better to always plant at least two trees to be certain of pollination.

The Romans brought with them spices such as ginger, pepper and cinnamon, and herbs including borage, chervil, dill, fennel, lovage, sage and thyme, all of which have remained staples of the British kitchen.

As you get older your own problems are not that interesting.

Chickweed is regarded by most gardeners as just that - a weed - but is excellent in sandwiches or salads.

Pulmonarias need splitting every two or three years, as they rapidly develop into a doughnut with an empty centre that quickly gets filled with weeds.