Anna Pavord: "Forget raised vegetable patches - veg are better off grown at ground level"

A raised bed edged with wooden planks is time consuming and will have rotted within five years, argues our horticultural expert

It is perfectly possible to grow vegetables in your garden or on an allotment without making raised beds. There. I've said it. I'm swimming against the tide here, but I've always thought it odd that gardeners (especially those new to gardening) so often seem to think first in terms of timber.

I can see part of the appeal. A raised bed edged with wooden planks gives an illusion of order in what may be a sea of intractable weeds. If you are short of time, as so many gardeners are, a raised bed presents an area that you can weed and maintain in a single session. We understand that not treading on soil is A Good Thing and a series of parallel raised beds with earth paths between allows us to sow and plant without setting foot on the sacred tilth.

But constructing a timber-edged bed is time consuming. Much new softwood is rubbish and will have rotted within five years. We found this with board edgings that we used along the edges of the paths on the bank. Soil immediately alongside a board edging will warm up, and create the perfect habitat for red ants. Their burrowings disturb plants but they also excrete a substance which can be toxic to their roots. Even if your board edgings don't attract ants, you may find that in a hot summer (such as the one we've just had) the soil next to the boards dries out very fast which means seeds there don't germinate and plants don't grow as well as they should.

Raised beds have always been around. Asparagus, for instance, has traditionally been grown in raised beds, but for a good reason. Asparagus, being a plant of sand dunes, does best in light, well-drained soil. But a raised bed used to be just that, a simple, unboarded affair, constructed in the way that Joy Larkcom describes in her invaluable book, Vegetables for Small Gardens.

Beds, she explains, can be anything from 1m to 1.5m wide with paths of 30-38cm between. The point is that you should be able to cultivate the beds from either of the two long sides, without ever having to step on them. But Larkcom's first instruction in the process of making a bed is: "Initially cultivate the whole area to a depth of 15-20cm". Too often this doesn't happen and a raised bed is made directly on top of whatever compacted soil, rubble or rubbish lies beneath.

After marking out the position of the beds, Larkcom then suggests spading 15-20cm of soil from the paths and using that to raise the beds. She favours un-edged, flat-topped beds with sloping earth sides, which can be cultivated right up to the edges because there are no boards causing the soil to overheat. Finally, she says: "Rake the bed to level it, then shape it into a curved shape if required. Firm the sides with the back of a spade."

The great thing about Joy Larkcom is that you can see her doing the job she is describing. She has experimented more than most people with the best ways of cropping a small patch and her advice is always worth listening to. Another important point was made by the late, great Geoff Hamilton, who through his role as TV's Number One Gardener was chiefly responsible for introducing the concept of raised beds to the wider public.

He explained that a raised bed was likely to be most useful on heavy ground, or ground that was exceedingly poor. On heavy ground, a raised bed gives better drainage; on poor ground you can build up a growing area rich in humus and all the other things the underlying ground does not have. But on light, fast-draining ground, a raised bed can compound the difficulty of water disappearing faster than plant roots can take it up. Regular mulching with bulky organic compost will help prevent this and, on any raised bed, is necessary to maintain fertility.

That's another thing that gets forgotten. You can only crop intensively (one of the much-vaunted advantages of a raised bed) if you feed liberally. And that means bulky stuff, not just Miracle-Gro. Only by adding bulky humus will you improve the soil's ability to hang on to more moisture when it comes. It feeds too, though more slowly (and sustainably) than feeds from a bottle. Orientation matters as well. If you lay out your beds on an east-west axis, then one of the long sides of each bed will face the sun, which the plants will enjoy.

One of the disadvantages of boarded raised beds is that it fixes the design of a plot. Having done all this carpentry, you are not likely to dismantle it until rot and decay forces your hand. But a veg patch can be a very engaging moveable feast, if you have the freedom to lay it out each year in a different pattern. One year it could be a noughts-and-crosses board of nine equal squares, another year a star-shaped pattern of eight triangular and kite-shaped beds radiating out from a central point, or spirals of crops whirling in a Catherine wheel of marigolds and parsley, radish and viola.

In our old garden, I played around very happily in this fashion, with never a raised bed in sight. One year, zinnias made a spectacular centrepiece, sown direct into the soil. I've never grown such good zinnias since. Around them were beds of different lettuces, beetroot, French beans and two beds of sweetcorn standing opposite each other. Surrounding the circle of zinnias was a sprawling edge of squashes.

A veg patch no more than 5m square can easily give you between eight and 10 different compartments for planting, depending on the layout you choose. When Nori and Sandra Pope were gardening at Tintinhull in Somerset, they laid out a plot in the walled garden like a Mondrian painting, interlocking squares and rectangles of beans and sweet peas, kale and courgettes. It was spectacular, as well as productive. So before lashing out cash on those planks, those stakes and those screws, remember, there are other ways of growing veg. And with the money you've saved, you can buy young plants of your favourite vegetables instead of seed. That really does make growing your own an easier proposition.

WEEKEND WORK

WHAT TO DO

* Runner beans and French beans that have cropped to exhaustion (or stringiness) should now be cleared off vegetable plots together with any weeds.

* Globe artichokes that have sprouted new growth may need protection against frost.

* Let house plants drift into semi-dormancy. Cut down on feeding (once a month is plenty) and watering, but keep the atmosphere round the plants slightly humid by misting over leaves, or standing pots on a layer of damp pebbles.

* Shading should be washed off greenhouses and an insulating film of bubble polythene fixed in its place.

WHAT TO SEE

* Derry Watkins's enthusiasm never wanes, which makes her one-day courses great favourites with gardeners who definitely feel they are running out of steam. On Tuesday 4 November you can brush up on pruning techniques – shrubs, fruit trees, perennials and grasses – to enhance form and increase vigour and flowering. The £75 price includes homemade lunch. Ring 01225 891686 to check availability before booking.