How to Grow Asparagus

how to grow asparagus

If you're an Asparagus fan this is a vegetable that really pays to be home grown - you can save yourself a fortune on shop prices even though the English asparagus season is quite short you can be cutting a couple of bunches a week from late April to the middle of June.

After that you have to stop cutting to let the plants grow and complete their life cycle though could cut a little of the Fern from the well established plants to use in flower arranging if you do so sparingly.

The main drawback with growing asparagus is the space it needs as its a perennial crop which occupies the ground full time and since it takes several years to settle in you can't harvest much for the first three years  - but it’s worth the wait!

When To Plant 

Plant during April in well drained ground or in slightly raised beds which have had lots of organic matter dug in during the winter working some general purpose fertiliser just before planting. Dig a generous planting hole for each crown and spread the roots out well then cover with five cm of soil.

When a shoot start to appear above the ground gradually earth up the plants until they're growing along ridges up to 15cm high spacing 30 to 45cm apart with 90cm between rows -

Care Tips

Fertilise in April & Remove The Weeds

Water plants in well early and each April sprinkle general fertiliser over asparagus beds. Water if the weather is very dry during the cropping season hand weed beds regularly - don't let the weeds grow large or use a fork for removing them as asparagus plants are shallow rooted and dislike disturbance - A Speed Hoe is ideal for as an alternative.

Don't cut any emerging spears for the first two summers after planting and then only take a light crop for the first few weeks of the cutting season in year three. 

From then on you can harvest as much as you like until mid June or the very end of that month if you have old established plants.

Cut Yellow or Browning Fern in Autumn 

From mid to late June onwards stop cutting to allow the ‘fern’ to grow up. Cut yellow or browning fern down to 5 cm above ground in autumn then weed over the bed and mulch the soil generously with well rotted organic matter. 

Asparagus Harvest

Start cutting asparagus spears from the time they first start to appear towards the end of April and the crop until mid June -  cut them as soon as they reach about 15cm tall and look like the ones you see in the shops! Use a strong knife to cut spears off 5 cm below the surface and then fill the hole this leaves with soil to prevent pests getting in.

Possible Problems

Overcrowded Seedling Beds

If self sown asparagus seedlings are left alone they grow quickly and are soon indistinguishable from the plants that are meant to be growing in a bed. These seedlings do not produce good yields and their flavour is often poor. They also overcrowd beds which reduces the yield from your named variety so keep on top of the weeding.

Thin Spears

Thin spears are usually caused by weak plants that have cropped too early, cut too heavily in previous years or not fed sufficiently or all three!

Pests like Slugs or Black Caterpillar 

Slugs can attack emerging Spears but the main pest is likely to be the asparagus beetle - it's about 8mm long with yellow and black wing cases and appears from may onwards. Both it and its greyish black Caterpillar like lavae feed on spears and mature foliage. 

The good news is that both are easily seen and can be picked off by hand - look out for the clusters of black eggs on foliage and pick leaves off too. Clean up the beds in autumn to discourage over wintering pests and burn and cut foliage to kill any that may be lurking within.