How to grow asparagus

Val Bourne / 16 April 2020

Asparagus takes a few years to get going, but for someone with enough space and patience it can be an extremely rewarding perennial crop.



Growing your own allows you to harvest really fresh vegetables and get them from plot to plate within minutes. As a result they’re more nutritious and vitamin-rich, but more importantly really fresh vegetables are full of flavour and deliciously tender.

Home grown asparagus, one of the culinary delights of early summer, has a completely different flavour from the bunches of asparagus you can find on supermarket shelves. It’s extremely good in kitchen gardens, because it crops in the hungriest moment of the gardening year when little else is available. A good bed can be cut between mid-April and mid-June and this is the reason why country house gardens always have a large bed of asparagus. It fills the hungry gap.

Asparagus is equally good in a garden or on an allotment, as long as you have enough room to plant ten or twenty crowns. It needs a dedicated bed of its own, because it stays in the ground year after year. Many an established asparagus bed is over 20 years old, but still delivering delicious spears. It comes into season in May, or earlier, and then you stop cutting in mid-June and allow the ferny leaves to develop so that the crop regenerates for next year. The traditional day to stop cutting is Midsummer's day, June 21st. You can’t cut any spears until the third of fourth year.

Older heritage varieties have male and female spears and these vary in thickness. Male plants have thick spears and the females are almost spindly. However most modern varieties are F1 hybrids producing all-male spears, so it's important to source named asparagus crowns from a good supplier. Don't be tempted to raise asparagus from seeds because your plants are likely to be variable. Remove any berries, if you see them in your plants, to prevent poor seedlings from infiltrating your bed.

Varieties of asparagus

‘Connover’s Colossal’ AGM
Still highly popular, despite being launched in 1872, this early, heavy cropping variety produces green spears. Does well on lighter soils.

‘Mondeo’ F1
All-male, disease resistant hybrid with chunky tight-tipped green spears. Excellent flavour.

‘Guelph Millennium’ AGM
This Canadian-bred variety, suited to cooler conditions, produces high yields of purple-tipped, green spears. It’s less fussy about soil too.

‘Backlim’ F1 AGM
A mid- to late-season male variety giving a consistent supply of large, smooth spears with well closed tips. A very reliable, healthy performer in the kitchen garden. This variety can be blanched to produce white spears.

Portlim F1
A new 100% male hybrid producing consistently thick green spears. In warmer weather the tips of this variety stay tightly closed and the smooth spears are completely cylindrical.

Gijnlim F1 AGM
An early season, high yielding male variety producing medium-thick, mid-green spears with closed purple tips. Said to have a superb flavour.

‘Pacific Purple’
Raised in New Zealand, this has stringless purple spears that turn dark-green once cooked. Purple asparagus contains more antioxidants and this one is more tender and sweeter than most green varieties, so it can be eaten raw.

When to plant asparagus

April and May are the best months to plant a new asparagus crowns. However crowns can also be acquired in autumn.

How to plant asparagus

Choose a sunny, warm position and avoid frost pockets.

If you have heavy soil that retains water, build up a gentle mound (about a foot high) to aid drainage, planting the crowns at the top of the mound. You can also plant in raised beds.

Always prepare the soil well before planting. Weed the bed thoroughly in the months before, removing all pernicious weeds. Being weed free is essential as these shallow-rooted young plants resent competition.

Plant twenty crowns if you can, to ensure a reasonable crop during the six week cutting season.

When your crowns arrive, they will look rather like long-legged spiders because their roots splay out horizontally. This indicates that they are shallow rooted and cannot dig deep for water or nutrients.

Soak the new crowns for an hour or two first (if they look dry) and then spread out the roots to form a wagon wheel shape.

Space each crown a foot apart (30 cm) in rows over a yard apart (1 m) to a depth of four inches (8 cm). Loosely cover with soil.

Keep newly planted crowns watered in their first growing season.

Caring for asparagus plants

Hand weed the bed, or hoe very carefully.

Do not overfeed asparagus. A light sprinkling of blood, fish and bone round each plant in spring is enough.

Mulching asparagus plants

Mulch straight after cutting has stopped, in late-June, with a two-inch layer (2.5 cm) of garden compost. This will discourage weed seedlings from germinating.

Cutting asparagus back

Cut the ferny stems down once the foliage begins to yellow, usually after the first savage frost.

Don’t add the foliage to the compost heap: it may be harbouring asparagus beetle.

Leave one inch of growth showing and then weed the bed carefully.

After cutting down, add another layer of organic mulch making sure it goes on to warm soil. This will rot down and feed the crowns. Do not apply mulch over cold soil.

Self-seeding asparagus plants can be a nuisance. If you spot any small seedlings, remove them because they form inferior plants.

Harvesting asparagus

After about four years your plant should be really established and the spears ready for harvesting. The plant comes into season in May, harvest spears every other day but stop harvesting in mid June - Midsummer's day is the traditional time to stop harvesting asparagus. 

The nitty gritty

Only consider this crop if you have enough for ten or twenty crowns, otherwise you will never get a crop.

Plant them in weed-free conditions in late-spring (once the soil is warm) choosing a sunny position. Water in well.

Be patient, it will take at least four years for this crop to deliver harvestable spears.

Keep an eye out for female plants that produce seed pods (these look like small berries) and remove them to prevent inferior seedlings popping up.

Asparagus beetle

Keep an eye for out asparagus beetles. They look like elongated ladybirds and they lay their eggs on the foliage in June.

Pick them off and destroy them, checking regularly for more.

Did you know?

Asparagus produces rather phallic spears and the Greek spargao (meaning turgid) reflected the tumescent shape of the spears. The sandy land close to Venice produced masses of white asparagus in the 16th century. When the Huguenots fled France in 1685 they brought this vegetable with them and planted fields of it near London. Battersea asparagus was rated the best and the earliest and two hundred and sixty acres were once devoted to the crop.

Asparagus, a wild plant from Mediterranean coastal regions, does best on lighter alluvial soils that warm up quickly in spring. Most commercial crops in Britain are grown in warmer areas like the Vale of Evesham which has rich, loose soil.

Where to buy asparagus

Blackmoor Nurseries www.blackmoor.co.uk
Pomona Fruits www.pomonafruits.co.uk



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