Grow asparagus

Asparagus is easy to grow. Anyone with a piece of ground to play with can reap the benefits. Depending on whether you use bare-rooted crowns, seeds or seedlings, you can start planting in winter or spring.

Getting started

The first important task is to choose a bed. Asparagus is a perennial plant and it needs a dedicated bed where it can grow and develop for many years. Be sure to choose a sunny site where the soil drains well.

A 1m by 1m bed will comfortably house four plants spaced 45–50cm apart, and is probably enough to feed two people. If you have three or four asparagus lovers in your household, go for a bed that’s at least 1m by 2m. That will support 8–10 plants.

Whether you’re preparing your natural soil or using soil you’ve purchased to fill a new raised bed, make sure to add plenty of compost or aged manure to stimulate soil life and set up your crop for years of production. Check the soil pH. If it’s below 6, add garden lime to sweeten it up.

Seeds, seedlings or crowns?

You can start your asparagus from seeds, seedlings or crowns (little bunches of buds and fleshy roots from plants that are 1–2 years old). Sow seeds in containers in spring, keep moist, and they’ll come up in 2–3 weeks. Garden centres often stock seedlings, and these can be planted out in spring once the risk of frost has passed. It takes a good 2–3 years to see a harvest from seedlings.

Crowns offer an earlier harvest because they’re already established. These are sold bare-rooted in winter and can be planted in late winter to early spring. When planting crowns, dig a hole 30cm deep, then use the excavated soil to make a mound in the hole. Spread the crown’s roots evenly over the mound, then backfill, with the centre of the crown just below the surface. Water in well.

Growing and harvesting

Newly planted crowns will start shooting in spring. Don’t be tempted to harvest spears in the first year. Let the plants grow freely to build some bulk below ground. Each spear will quickly expand into a wild ferny stem about 1m tall. Keep the bed moist throughout the growing season, and spread a little fertiliser in spring and late summer.

By winter, the ferny growth will yellow as the plant enters dormancy. Cut everything back to ground level and top-dress with more compost or aged manure. Feed and water it in to get things moving. In your second spring (or third for seedlings), you can start harvesting the spears. When they’re 15–25cm long, use a sharp knife to cut them off near or just below the surface. Harvest for up to 10 weeks, then allow the ferny growth to develop again to build the crown’s energy stores over summer.

Asparagus is dioecious, which means plants bear either male or female flowers, but you won’t know for sure until they bloom (females produce tiny red berries in autumn – don’t eat the berries, they’re poisonous). Males tend to produce thicker spears, so you may decide to replace the females, or just let them be – the female spears are equally delicious, and you can use their seeds to start new plants!

Header image credit: iStock

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