How to grow Asparagus

How to grow Asparagus

If there’s one vegetable that’s got the last word in culinary perfection, it’s asparagus. Smooth, flavoursome spears (shoots) of unrivalled succulence are the name of the game here, making this the kitchen garden ingredient of any chef’s preference.

Its brief season of availability has given asparagus an almost legendary status. Like the first sweet strawberries of summer, the moment that asparagus hits the shelves is eagerly anticipated. It seems that as soon as those tender spears appear, the season is almost over. 

Maybe it’s this fleeting presence of awesome taste that has given asparagus cultivation something of an air of mystery. Yet with the correct ground preparation and the completion of a few simple annual tasks, an enviable crop of spears will be yours every spring. 

Asparagus is one of a handful of perennial vegetables, sitting in the same ground for at least 10 years and often up to 20. It may seem expensive and time-consuming to begin with, but once plants are established, you can expect a cut of 10 to 20 spears per plant. Work that out over its 20-year lifespan, and you’ve got an awful lot of culinary ecstasy for the minimum of financial outlay and annual effort!

Modern, all-male F1 hybrids have done a lot to advance the attraction of asparagus to the home-grower. These vigorous varieties give a solid performance, often cropping earlier and giving bigger yields over the season. Grow them in a bed of their own where they won’t be disturbed by the comings and goings of short-lived vegetables around them. If space is at a premium, set them in among the decorative border where the post-harvest feathery foliage will form the perfect backdrop to flowering ornamentals.

Preparing the Ground for Asparagus

Meticulous ground preparation is essential if asparagus is to thrive. Unfortunately, you can’t grow asparagus in containers very successfully. If you’re wondering ‘can I grow asparagus in pots’, or ‘can I grow asparagus indoors’, it’s best not to. 

Remember that you are effectively laying the groundwork for two decades of growth, so time spent now will be repaid many times over in the years to come. There is little point rushing this job!

Asparagus prefers a free-draining but nutrient-rich soil that’s not too acidic. Aim for a pH of around 6.5-7.5, adding lime to the soil if yours is below this. Pick a position in full sun, free of frost pockets, where the plants can grow undisturbed and protected from strong winds. Some shade is tolerable, but you will get a better performance when plants can draw on good, steady sunlight. 

Bear in mind that young trees and shrubs nearby may grow larger to eventually cast shade over your asparagus crop. Plants may be grown in any plot that satisfies the above requirements, but heavy clay that hasn’t been improved in the past may prove a challenge. Consider dedicating an entire raised bed to asparagus in these circumstances, when the extra depth of soil will make all the difference.

Prepare the ground the autumn or winter before planting by digging in ample well-rotted manure or garden compost – at least a bucketful per square metre. About a week prior to planting, rake in a general-purpose organic fertiliser, such as bonemeal to give the soil a final boost for your new introductions.

How to Grow Asparagus Crowns

You can grow asparagus from seed, or by planting rootstocks (usually one year old) called ‘crowns’. It’s best not to try growing asparagus from scraps, or growing asparagus from cuttings, as you’re not guaranteed success. 

Growing from seed is cheaper than starting from crowns, but you’ll have to wait another year before you can begin harvesting. Considering a bunch of supermarket asparagus costs as much as two ready-to-plant crowns, in most circumstances the latter option is well worth the investment. Ten crowns costing about £15 should supply more than enough spears for the average family. 

A certain type of asparagus does grow wild: it’s a coastal plant that you might find in Dorset, Cornwall and Wales. Finding wild asparagus is quite rare, and it is very different to garden asparagus.

Crowns are generally planted in late March or April into prepared ground, though you can establish them in the autumn, too. Whether growing in raised beds or open ground, begin by digging out a trench 20cm deep and about 30cm wide. If your soil hasn’t been cultivated much in the past, an additional layer of compost or manure may be placed into the bottom of the trench. Cover this with a similar depth of soil to add more nutrients for the roots to grow into. 

Now add a line of compost along the bottom of your trench to create a raised mound. This will lift the buds of the crowns above the roots and help excess moisture to drain away from the delicate buds. Make sure that the roots are completely hydrated by soaking them in a bucket of water while you prepare the trench.

Set your crowns into the trench at least 30cm apart, straddling the roots either side of the raised mound. Then, fill back the soil so that the buds sit just beneath the surface. The trench can be filled in gradually during the growing season, so that by autumn, the level of soil in the trench will match that of the surrounding ground. If you intend to grow more than one trench then set these 45cm apart to give each row plenty of space.