How to grow asparagus

Asparagus is seen as a luxurious and desirable vegetable, with an amazing taste making it a top-class serving and ingredient.

But don’t pay huge supermarket prices – grow your own great-value asparagus crop instead!

How quickly does asparagus grow?

When established, an asparagus crown – the base of the stem with all roots attached – can produce a crop for as many as 20 years.

Asparagus needs two years to establish and from the third season onwards you can expect 20 to 25 succulent spears per plant.

Main varieties of asparagus

  • The Millennium variety of asparagus gives a high volume of slim, tender spears.
  • Ariane is a plant that produces thicker, meatier asparagus spears.
  • Pacific purple is favoured raw and is perfect for tasty salads.

When to plant asparagus

Asparagus crowns should be planted from March into April.

Where to plant asparagus

Asparagus plants will do best in a sunny, wind-sheltered spot. Avoid ground that’s previously had asparagus or potatoes, as this may encourage pests and diseases.

Preparing the soil for asparagus

Asparagus can grow in any free-draining soil that has lots of fresh compost dug in, but the vegetable thrives in sandy substances that are slightly alkaline.

Use a soil-testing kit to work out the pH level of your soil, adding lime if needed to make it less acidic.

How to plant asparagus

  • Dig small trenches about 12inches (30cm) wide and 8inches (20cm) deep.
  • Along the bottom of the trench, make a gap 3inches (8cm) wide for the roots to spread over.
  • Plant asparagus crowns 12inches (30cm) apart and cover them with only 2inches (5cm) of soil.
  • Water and keep watered during dry conditions.
  • Fill the trench in fully in the autumn, after the first season has finished.

Growing asparagus in containers

Asparagus crowns can be grown in large containers, patio grow bags or gro-beds for up to five years after planting.

What to do in the first autumn

  • Remove any weeds from the soil by hand, to prevent damage to the plant’s roots.
  • Remove any berries that appear, as this stops self-seeding after the first season.
  • In autumn, cut the yellowy fern foliage down to 1inch (2.5cm) above the ground.
  • In the following spring, a general fertiliser can be added to the ground.

When to harvest asparagus

In the third year, the asparagus spears can be harvested from mid-April to the middle of May.

When spears are 6inches (15cm) high, cut them with an asparagus knife by severing the plants 3inches (8cm) below the soil surface.

Stop harvesting in mid-June, which allows the plant to develop its foliage and provide energy for the following growing season.

What to do in autumn after harvesting

In early autumn when the ferns turn yellow and die back, cut the dead fern back to within 3inches (7cm) of the soil level and destroy the waste. Continue weeding the soil.

What to do in the spring before growth restarts

Mulch (spread) the soil bed with well-rotted organic matter and add a dressing of well-balanced compound fertiliser.