30cm between rows
Asparagus is a delicious early summer perennial vegetable grown for the tender young shoots, known as spears. It’s a delicacy that might seem out of reach as a grow-your-own crop, as it needs space and long-term commitment. However, although you won’t be able to harvest the spears for the first few years, it’s well worth the wait. Also, once established, an asparagus bed is relatively easy to maintain, and you can expect to reap the rewards for as long as 20 years.
How to grow asparagus
Asparagus grows best in light, well-drained soil. You can still grow asparagus on heavy soil but it’s worth creating a raised bed. Choose an open, sunny site and make sure it’s well prepared with plenty of organic matter and is free of weeds.
If you’re lucky enough to inherit an established asparagus bed, don’t be tempted to replant with new crowns. If you want to plant more asparagus, choose a new site where there’s no risk of asparagus diseases. It’s also not advised to plant asparagus where you’ve previously grown potatoes.
How and when to plant asparagus
Asparagus can be raised from seed, but the most reliable method is to plant one-year-old dormant plants called ‘crowns’ in March. Some varieties can also be planted in autumn.
Watch Monty Don‘s comprehensive guide to planting bare-root asparagus crowns, below. Monty shows you how to prepare the crowns for planting and how to prepare the soil so this long-term crop will thrive for many years to come:
If you want to try sowing asparagus seed, you can sow in modules in late winter or directly into the ground in spring. However, you will need to wait at least five years, before harvesting.
How to care for asparagus plants
Keep newly planted asparagus crowns well-watered and weed-free. Let the crowns develop plenty of ferny foliage so they can become strong and established. Don’t harvest asparagus in the first two years – harvesting before the third season will weaken the plants. At the end of the growing season cut foliage back to 10cm above soil level and mulch with well-rotted compost in autumn. Weed regularly and pick off asparagus beetles in spring.
Here, Monty Don demonstrates how to cut back asparagus foliage at the end of the season, and how to mulch around the plants:
When to harvest asparagus
Don’t harvest asparagus for the first two years after planting. In the third year, start cutting the spears in mid-April when they are 18cm tall. Use a sharp knife, cutting the spears 2.5cm below the level of the soil. In warm weather, harvest every two to three days for up to four weeks. In subsequent years, you can harvest over a longer period. Stop harvesting in mid-June, as this will allow the plant to build up reserves of energy for next year. This would be a good time to give plants a feed with a general fertiliser, too.
Asparagus is best eaten freshly cut for maximum flavour. However, it can be stored in the fridge for a few days.
How to cook asparagus
Asparagus is delicious steamed or grilled and can be eaten on its own or incorporated into other dishes such as salads and risotto. Trim the spears with a knife or by snapping, to cook the tender top half.
Growing asparagus: problem solving
Look out for asparagus beetle from late spring onwards. Pick off any larvae or beetles that you see and burn old stems at the end of the year to destroy any overwintering beetles.
Asparagus can also be affected by violet crown rot, a soil-borne disease that causes the crowns to rot. In this case you have to dig up the plants, burn them and start afresh in a new site.
Asparagus varieties to try
- Asparagus ‘Mondeo’ – an all-male hybrid that is suitable for both spring and autumn planting with high yields, cropping early in the season with good disease resistance.
- Asparagus ‘Guelph Millennium’ – suitable for spring or autumn planting, this Canadian-bred variety is very cold tolerant, with a high yield and suits most soils.
- Asparagus ‘Gijnlim’ – an early-croppping variety, with green spears with dark purple tips.
- Asparagus ‘Vittorio’ – this is a so-called ‘white’ variety. The spears have to be earthed up with soil for blanching.
- Asparagus ‘Connover’s Colossal’ – a reliable heritage variety with high yields.
- Asparagus ‘Jersey Knight’ – very heavy cropper with good disease resistance.