Asparagus can be raised from seed or young dormant plants - crowns - can be purchased. Sow seeds of an all-male F1 hybrid singly into modules in February and transplant in early June. Most gardeners choose one-year-old crowns, planting in March or April.
Fork over the prepared area and dig a trench 30cm (12in) wide and 20cm (8in) deep. Work in well-rotted manure in the bottom, cover with 5cm (2in) of the excavated soil and make a 10cm-high (4in) ridge down the centre of the trench. Place the crowns on top, spacing them 30-45cm (12-18in) apart (right). Leave 45cm (18in) between rows and stagger the plants. Spread the roots evenly and fill in the trench, leaving the bud tips just visible. Water in and mulch with 5cm (2in) of well-rotted manure.
Asparagus beds must be kept weed free - best done by hand as the shallow roots are easily damaged by hoeing. Mulching discourages weeds and retains moisture. Apply 100g per sq m (3oz per sq yd) of a general fertiliser in early spring and repeat once harvesting has finished.
To avoid top-growth breaking off in wind and damaging the crown, use canes and twine either side of the row for support. Remove any female plants (those bearing orange-red berries) and any seedlings.
Allow the foliage to yellow in autumn before cutting it down to 2.5cm (1in).
To harvest, cut individual spears with a sharp knife 2.5cm (1in) below the soil when they are no more than 18cm (7in) tall. In warm weather, harvest every two to three days for best quality spears.
Do not harvest for the first two years. In the third year, pick from mid-April for six weeks, and in subsequent years for eight weeks.
