Asparagus is a perennial vegetable, which makes it good for growing in an area where it won't be disturbed. Once planted the plants can crop for up to twenty years so a bit of care at the initial stage pays dividends. For a decent crop, asparagus needs to be given lots of space and is ideal for a large garden or allotment. It thrives in sun and well-drained soil but needs some protection from the wind. Alternatively, grow in a raised bed. Asparagus is not suitable for containers and won't do well if planted in heavy clay soils or in a shady spot.
Asparagus plants are either male or female. Male plants produce more and better spears, so many modern cultivars are all-male. If any female plants do appear, they will be noticeable because they produce orange-red berries. If you are growing an all-male cultivar, you will need to remove any female plants as well as any seedlings that appear. We love Gijnlim (male ) that gives heavy crops a year after planting.
- In spring dig a trench 30cm (12in) wide and 20cm (8in) deep. Work in well-rotted manure to the bottom of the trench and cover the base with a 5cm (2in) layer of the excavated soil or compost.
- Make a 10cm-high (4in) ridge of soil down the centre of the trench. Place the crowns on top of this ridge, spacing them 30-45cm (12-18in) apart within the row. Spread the roots evenly and replace the rest of the soil, leaving the bud tips just visible.
- Leave 45cm (18in) to 60cm (24in) between rows and stagger the plants between adjacent rows.
- Water in and mulch with 5cm (2in) of well-rotted manure or other weed-free organic matter.
- Water newly planted crowns thoroughly and keep damp during dry weather. Succulent spears may appear soon after planting, but avoid the temptation to harvest them or you'll weaken the crowns
- During their first two years of growth, plants should be left to form lots of ferny foliage - cut down the stems in autumn, leaving 5cm stumps above the ground.
- To prevent competition, keep beds free of weeds.
- Most plants are ready to be picked two years after planting, although several modern varieties have been bred for earlier cropping.
- To harvest spears, wait until they're about 12cm long and remove them with a serrated knife, cutting them off 7cm beneath the soil.
- Stop harvesting in mid-June to allow the plant to build up its energy for next year, and give plants an extra boost by feeding with a general fertiliser.