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About asparagus

Asparagus is a perennial vegetable, which makes it good for growing on plots where it will not be disturbed. However, it does take a long time to grow to maturity, so make sure you are planning to stay a while to see the fruits of your labour.

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 will sulk if planted in heavy clay soils or in a shady spot.

What to do

Soil preparation

• Asparagus plants can remain productive for up to 20 years, so it's worthwhile spending time on preparing the bed to give them a flying start in life.
• If you can, start in autumn by digging over thoroughly, mixing in plenty of well-rotted farmyard manure, and removing all perennial weeds.
• A week or so before planting, scatter some general fertiliser granules over the area (about 90g/sq m is ideal) and fork in, before raking the ground level.

How to plant

• You will need about an hour to plant 10 crowns. Make a straight trench, 30cm wide by 20cm deep, and then pour soil down the length of the trench to make a 10cm high mound.
• Next, carefully take your asparagus crowns and sit them on top of the mound, spreading the roots out either sides - plant crowns 30cm apart and then cover with about 5cm of soil, which has been sifted through a riddle or sieve.
• Cover the plants with more sifted soil as the stems grow, aiming to completely fill the trench by autumn. Subsequent rows should be spaced 30cm apart.

Aftercare

• 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.

Harvesting

• 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.

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Five to try

• Gijnlim - heavy crops one year after planting
• Jersey Giant - dark green spears with a purple head
• Jersey Knight Improved - thick, but tender spears
• Purple asparagus of Alberga - Italian heritage variety with purple spears
• Backlim - thick, green spears