Turf love: Dandelions, thistles and common mouse ear can be a menace to your lawn. Here, Anna Pavord gets tough with the bullies ++ Diary of a Dorset garden

I'm fretting about our front lawn. And I'm fretting that I'm fretting. I can't believe that I've finally joined the ranks of those who care about the state of their turf. It's pathetic. All my life, I've only expected a lawn to be greenish and flattish. Now a plague of dandelions makes me jump up and down with rage. Weeds with wide spreading skirts - dandelions, plantains, thistles - are a menace in lawns. By flattening themselves against the ground, they prevent anything else sharing their food and drink. For them, it's a great survival strategy. For grass, it's a disaster.

For the first time in my life I bought a lawn weedkiller (Verdone Extra at £13.93 a litre), cheered by pictures on the pack of all the things this stuff could destroy: dandelion, daisy, plantain, common mouse ear, white clover, black medick and lesser trefoil. Carefully we paced out ten square metres of lawn and applied the herbicide, mixed according to instructions (15ml in five litres of water). Result? Dandelions that coughed and spluttered a bit, but hung grimly on to their growing ground. After a while I did what I've always done before and whipped them out with a kitchen knife.

As a result of that particular attack, the lawn is dotted with circles of bare earth where the dandelions - more than two hundred of them - had dug themselves in. Now it needs a makeover, a lawnish equivalent of a day at the spa. The first job was de-thatching (I thought of it as exfoliation), and I bought a special rubber-tined rake to do it. This deals with moss too, but moss hasn't yet found the front lawn, which is in a very open, sunny situation. It's a well-drained bit of ground too, and poor drainage is one of the most frequent causes of moss in lawns.

Thatch is the descriptive word for all the bits of dead grass, foliage and rhizomes that make a mat under the green growing stuff. It builds up faster if you use a mower with blunt blades that flattens shoots of grass rather than cutting them. A certain amount of thatch is good, because it slows down the rate at which moisture evaporates from the ground underneath. But if you have too much of it, it has the opposite effect. It stops water getting through to the soil and by absorbing it, makes the lawn soggy.

When you've raked up the worst of the thatch, you can run a mower quickly over the lawn to collect up the bits you missed. Now it is ready for the second step of the beauty programme - the bit we haven't done yet. This involves punching holes in the turf with a hollow tiner. I'm not sure beauty therapists have developed an equivalent to this, though you could think of it as opening up the pores...

You can do this aerating with a garden fork, pushing it in at intervals and wiggling it about. That creates a hole, but it also compacts the earth round the hole. The hollow tiner pulls out plugs of soil, extracting rather than compressing and makes a bigger, more useful hole.

The third stage is top-dressing, traditionally done with Leighton Buzzard sand - a coarse sand of the sort that plasterers use. The sand sifts down into the holes and the airspaces between the coarse granules stops the lawn from getting compacted. The sand, traditionally mixed with sieved soil and leaf mould (six parts sand, three parts soil, one part leaf mould), is an easy medium for grass to root into. I think we'll mix sand with John Innes No3 compost, sieve that over the lawn and brush it in with a birch-twig besom.

Finally, when the top dressing has settled, we can overseed. When we first came here, we turfed the lawn - a great extravagance; the seed I've chosen matches as closely as possible the composition of the original sward. It's a mixture called Badminton made up from browntop bent, creeping fescue and chewings fescue, with no rye and it's available mail order from Greenacres Direct (£21 for 1kg). One kilo is enough to cover 29 square metres, but if you are overseeding, it will cover much more, because you are not putting it on so thick.

Why is the lawn worth all this bother? Perhaps in a more sane frame of mind, I'll realise it isn't. But, since we made a new garden on a bank the other side of the yard, the lawn is pretty much all we have got in front of the house. It is very much in view, as the arms of the house fold in to enclose it and all the rooms look out on to it. I don't mind daisies and positively enjoy speedwell in a lawn, but dandelions are bullies. They simply had to go.

When Edwin Budding introduced the first lawnmower in 1832, he thought mowing might prove "amusing, useful and healthy exercise" for gardeners. How boring a life do you have to lead to find mowing amusing? But eventually his machine made lawns an obsession in Britain, where grass grows so easily and well. Despite the efforts of avant-garde designers, there is still an overriding conviction that a garden is not a garden without a lawn. In desert countries, they are the epitome of conspicuous consumption. Expatriate Brits marooned in Portugal, India and the Caribbean cling tightly to their lawns, liferafts in a sea of strangeness.

You see them growing against all the odds in countries where they need watering for at least six hours a day to keep them alive. Conversely in tropical countries, where magnificent aroids and bromeliads can give you all the ground cover you need, it seems contrary to insist on grass, which needs cutting at least four times a week.

Perhaps there is some deep-seated notion of security, of standards at work here. This was the territory mined so profitably by the early pioneers of the underground railways. Golders Green, Hendon and Finchley, a place of delightful prospects sang the posters, against sunlit images of semi-detached villas, each with its picket fence, its standard roses and its neatly edged patch of lawn.

Small town gardens are not the easiest place to grow lawns, but designers have an uphill struggle persuading garden owners that they would be just as happy with paving. Green is what the heart desires. There are also sound environmental reasons for choosing green, as turf merchants are quick to point out. Lawns absorb pollutants such as soot, dust and carbon dioxide. In the heat of summer (well, some summers), grass is considerably cooler than bare soil, very much cooler than concrete paving. A lawn of 290 square metres is enough to keep a family of four in all the oxygen they can gulp.

Lawns absorb rain, which paving throws away. Research carried out by the Lawn Institute in the United States showed that a well-kept lawn absorbs more water even than a field of wheat - up to six times more. But against the advantages, it's only fair to set some environmental disadvantages. The best kept lawns are likely to be the ones with the least diversity. The ideal is a monoculture: several million blades of fine grass living in a botanical ghetto. Species richness is a key element in the fight to safeguard the environment. A weedkilled lawn ends up on enemy lines. So now, as well as feeling enraged by the dandelions, I feel guilty too.

Greenacres Direct, PO Box 1228, Iver, Bucks SL0 0EH; tel: 01895 835235; fax: 01895 835343; www.greenacresdirect.co.uk