Spears of destiny: How to grow your own asparagus

It's asparagus season – and there's nothing better, argues our correspondent, than melting butter over your very own, home-grown crop.

The season for English asparagus has begun and we can look forward to six weeks' pigging out before the shutters come down again. But for proper feasts, you have to grow your own. The cost of asparagus (£4 a bundle at the start of the season) limits its pleasure. You need at least a bundle per person.

Asparagus requires commitment on the part of a gardener. Once planted, it stays in the same place. So you need to stay in there too, for the payback of the effort that it took you to plant it in the first place. But the craze for raised beds that has swept the allotments and back gardens of Britain is a bonus. Asparagus beds always were raised above the general level of a veg garden, because the plants, although they like to be well-fed, also like to be in well-drained soil.

Traditionally, beds were about 4ft wide and this is exactly the width that's recommended for the modern kind of raised beds, supported by wooden surrounds. You can get at it easily from all sides to weed, without ever having to tread on the soil. So if you've already got raised beds, then the most off-putting part of planting asparagus is already behind you. All you have to do is acquire the plants, which growers usually send out between mid-March and early June.

Another reason for growing your own is that, like sweetcorn, it spoils as soon as it is picked. Even if you take out a bank loan and clear the greengrocer's shelves to produce an asparagus feast, you will be tasting the vegetable at third best. "Asparagus is not fresh when it is gathered in the morning for the evening's dinner," warned Edward Bunyard sternly in his Epicure's Companion published in 1937. The saucepan must be steaming on the stove even before you cut the spears. Cook them standing up, with thef heads gently steaming in a dome of silver foil fixed round the top of the pan.

Left to itself, asparagus produces both male and female plants. The female ones make thin spears called sprue, and carry small red berries on the fern which grows up when you finish cutting the crop in early summer. But most asparagus is now 'all-male', and produces only fat spears. To have plenty to pick, twice a week for six weeks, you will need at least 30 roots (or crowns as they are more generally called).

The Royal Horticultural Society recently carried out a four-year trial of asparagus to find out which ones were most worth growing. They grew 11 different varieties and six of them got Awards of Garden Merit. One of them was 'Connover's Colossal', an old Victorian variety, still available and still good. The rest were all-male kinds: the Dutch varieties 'Backlim' and 'Gijnlim', French 'Dariana', 'Guelph Millenium', a Canadian variety bred especially for its tolerance to cold, and the handsome dark 'Stewart's Purple'.

As far as Bunyard was concerned, the size of an asparagus spear depended not on its breeding, but on the way you grew it. "There is only one secret to obtain large sticks, and that is to have the plants wide enough apart – four-feet square, say the French growers, for each plant," he wrote. But 30 plants set out at that spacing would take up the whole of most modern gardens. We have to be meaner.

Asparagus grows wild all over Europe and has been cultivated ever since the word 'epicure' was invented. In 77AD, Pliny the Elder was already writing about the complicated ways in which growers produced the pale, blanched stems that the Romans preferred. That's how you still find it grown in Switzerland and Belgium.

In Britain at least, wild asparagus is commonest in sand dunes and other well-drained sites near the sea. In the garden it likes similarly well-drained sandy soils, but not hungry ones. Pile on well-rotted manure or compost. Dig in some grit if the soil's sticky. Water must be able to drain away from the crowns. If they're permanently soggy, they rot.

You can grow asparagus from seed, which is certainly the cheapest method, but it takes time. Most gardeners buy crowns which may be from one to three years old. The youngest crowns are cheapest and transplant most easily, though you will have to wait longer before picking a crop. If you plant one-year-old crowns, you can cut just a few spears in the second year after planting and start cutting seriously in the third. Plant any time between now and the end of May, setting the crowns about 45cm/18in apart in rows that are at least 75cm/30ins apart. At this spacing, you will be able to fit two long rows in a raised bed 120cm/4ft wide.

First take out a trench and then make a raised saddle down the middle of each trench. Soak the crowns for two hours in a bucket of water, then plant them astride the saddle, with the roots draped down either side of the ridge. Make sure that when the trenches are filled in, the crowns have no more than 10cm/4in of soil on top of them.

Once planted, an asparagus bed will go on cropping for at least 20 years. That is why it is worth making a good home for them. They do not like competition, so keep the bed free of weeds and resist the temptation to grow flowers among the asparagus fern. It's a strong temptation, because the fern is so pretty. Traditionally, beds were dressed with salt in summer. The plants don't need it to grow, but the salt at least discourages weeds and slugs. Mulch the beds thickly with manure or mushroom compost in late winter. Cut down the fern only when it has yellowed and died back in autumn.

When the asparagus crowns are properly established, you should be able to cut 8-10 spears from each crown, but the crop will be spread out over six weeks. That is why you need so many crowns to get a decent picking at any one time. If you like gadgets, you will cut your spears with an asparagus knife. This has a curious semi-circular flattened blade with saw teeth, but a sharp knife does just as well. Cut the stems just beneath the surface of the soil when the spears are 13-18cm/5-7in high. If you start cutting at the beginning of May, say, you should stop by the middle of June. Young plants should be cropped more lightly.

Moles are great connoisseurs of asparagus and crunch on the shoots underground before they ever see the light of day. Slugs can also inflict damage. The black and yellow asparagus beetle overwinters on or near asparagus beds and lays its black eggs on the emerging shoots. Both the larvae and the adult beetle feed on asparagus foliage. Catch the beetles in jars. They drop straight off the foliage when you nudge them. But don't get depressed by the problems. Just think of the melted butter running down your chin. Once you have eaten your own asparagus, you will never be able to do without it again.

Seed and crowns of AGM varieties of asparagus are available from Suttons Seeds (0844 922 2899, suttons.co.uk); Dobies (0844 701 7625, dobies.co.uk); Unwins (0844 573 8400, unwins.co.uk); Kings Seeds (01376 570000, kingsseeds.com)