Decay and degradation

Compost. Nature's way with death. So why do the politically correct thing when you can do the right thing?

When the visit to the compost bins is the high spot of the garden tour, you know you are in the territory of an organic gardener. The OG may have trouble remembering the name of a particular flower or shrub, but here, in front of the shrines of rotting potato peelings, weeds, grass cuttings and farmyard manure, no question goes unanswered, no detail of the engrossing process of decay and reassimilation is left out.

The messianic zeal of a certain kind of organic gardener brings to mind the dictators of the last World War. A sentimental view of animals, an obsession with health and supposedly health-giving foods, vegetarianism and furious anti-smoking campaigns were all hallmarks of the Nazi period. Read The Nazi War on Cancer by Robert Proctor (Princeton, pounds 17.95).

"So what's new?" I find myself thinking rebelliously, as the self-regarding cant piles up. Some OGs give the impression that they invented the very process of composting; that worms give the bum's rush to anybody who is not a member of the Henry Doubleday Research Association. You can make good compost without the vast quantities of plastic and old carpet that seem an intrinsic part of a fully organic compost heap; and without the hideously intrusive noise of mechanical shredders that after grinding away for hours produce scarcely enough mulch to cover a mole.

I have a compost heap from hell - huge, untidy, unscientifically made. I am not proud of any of those attributes, but turning and tending compost do not come high on the list of priorities. I would never be without compost, though, and the heap produces the goods, which I retrieve by tunnelling under the mound like a miner. When the roof, the most recent, unrotted stuff on the heap, looks as though it is about to collapse, I pitchfork this material on to a cleared strip at the side and start building again.

The principles of composting are desperately important; the way that you get there is not. Anyone truly interested in gardening soon learns that soil is a precious commodity. It needs loving and feeding. You have to take the trouble to understand how it should be treated to keep it in good heart. But you can do that without plastic, comfrey, New Zealand boxes or any other totems of "correct" composting.

Composting is, in effect, recycling. So by having a compost heap rather than carting waste to a tip, you are doing your bit for the environment. Home-made compost is an endlessly renewable resource, unlike peat or loam. It is free and it is handy. No petrol is needed to haul it home from the garden centre. Households in the UK produce about 20 million tonnes of rubbish each year. Most of that goes into holes in the ground - "landfill" as it is delicately called. But green waste composted in small quantities at home, can become a plus, rather than a minus.

There. That's the Party Political Broadcast over. I can't say any of the reasons above are in my mind when I chuck weeds on to my compost heap. I just can't imagine gardening without one. It is the gardener's way of replicating what goes on in Nature. The alchemy of the process is fascinating. How can it be that nettles, potato peelings, grass cuttings and rotting sweet pea plants can be transformed into a single entity with the moist, dark, crumbly beauty of the best fruitcake? So how do you start? Not necessarily by spending money. You can make a compost heap anywhere, just by piling up waste into a heap. If this is contained within walls of some kind, it looks tidier and you can more easily pack the material into layers that heat up quickly. Heat is the key, but you also need air in a heap.

In a small garden, some kind of plastic container is probably the most practical way to make compost. Most custom-made compost bins are like dustbins without any bottoms. If you are a skip raider, you can make excellent compost pens using recycled pallets. Mine is built against a stone wall at the bottom of the garden. The two sides containing the heap are both made from pallets covered with chicken wire, which stops the compost oozing through the gaps. The front is contained only along half its length, so we can still tip a wheelbarrow on to the pile. Keen composters have two heaps: one cooking and one in the making.

Tea leaves, coffee grounds, egg shells, vegetable scraps, hair and dead cut flowers can all go on to a compost heap. Most of mine comes from garden waste: weeds, old pea and bean haulms, herbaceous plants cut down in autumn, grass clippings. But not autumn leaves. Those we rake up and pack into a leaf clamp. Leaf mould takes longer to make than compost, but is a fabulous mulch around shrubs.

The composting process, the alchemy, depends on two different micro-organisms. Mesophiles get to work first, creating heat as they process the different kinds of waste. When the heap gets too hot for them, thermophiles take over and the temperature rises even more quickly. But once all the most readily available foods have been gobbled up, the temperature of the compost falls and the mesophiles kick in again. Meanwhile, mites, centipedes, woodlice and worms will be tackling tough, chewy stems, beyond the capacity of the micro-organisms.

Air and water are vital to this process, but not sunshine, so there is no reason why your heap should not be in a dark, dank corner. The bigger it is, the hotter it gets. You won't get much action in a heap less than 3ft long and 3ft wide. Twice that size is twice as good. You can never have too much compost. Don't just use it as a dump for grass cuttings. They pack down tightly and get slimy, because not enough air is circulating in the mass.

The more air you introduce, the faster the heap will rot, which is why turning is so much in favour. I don't turn ours because there is always some more pressing task to hand. It still makes, but much more slowly. And because it does not heat up as much as a turned heap might, it harbours weed seeds, ready to germinate at the earliest opportunity. This is a problem only where you use home-made compost as a mulch. Much of mine goes to fill containers, or to line trenches for potatoes, peas and beans. Well buried, the seeds don't germinate. Sometimes we sieve it. This is Grade A stuff and, mixed with bonemeal, it makes the best possible compost to pack round plants when you are first planting them. Our soil is heavy clay, an intractable medium for tender new roots to penetrate. If the plant can be wrapped round with a more crumbly growing medium, it gets off to a good start.

Compost-making attracts obsessives. That matters only when they bore on to the rest of us about the Only True Way. Compost has been happily making itself for several trillion years. And will continue to do so, with or without our so-called improvements.

The shrine of compost-making is the Henry Doubleday Research Association's garden at Ryton-on-Dunsmore, Coventry, Warwickshire CV8 3LG (01203 303517). The garden is open daily (10am-5pm); admission pounds 2.50. Armchair gardeners can read `The Complete Guide to Garden Composting' by Dr Paul Bardos (Taylor Marketing Services, pounds 5.99). For stockists, contact Taylor Marketing Services, Oakwood House, 3 Moulton Park Office Village, Northampton NN3 6AP