Image by Liz West

Growing asparagus is a long-term investment. It’s a trust fund you can’t open for three years, but when you do, you’ll be eating the king of vegetables at a fraction of its supermarket price.

Asparagus are normally planted as one-year-old crowns, and spears aren’t harvested until the second year. Even then, it’s a limited crop as snipping off these shoots weakens the plant. But by the third year, the plants are raring to go and will happily yield spears for around 20 years.

Male plants offer the highest yields and do not self-seed as the females do, weakening the plant. They might be more expensive, but remember, this crop is an investment. The foliage is also extraordinarily beautiful, and acts as a perfect foil in an herbaceous border.

Growing asparagus
Plant in a light, well-drained soil. If you’re growing on heavy, sticky clay, it might be best to construct a raised bed for your asparagus. You will also need to make sure that the ground is free from perennial weeds such as bindweed and couch grass. Before planting, work in a great deal of well-rotted manure and, if you can get hold of it, seaweed, as asparagus is a coastal plant.

Plant the crowns around 15″ apart and 5″ deep. If you plant them any deeper, you will be harvesting fewer, but larger, spears. Do not delay planting once you have bought the crowns, as they dry out very quickly.

Maintaining asparagus
Keep the beds weed-free, but don’t use a hoe as this can damage the crowns. In the autumn, the foliage will turn bright yellow, and will need to be cut down to 3-4″ above the ground.

Watch out for asparagus beetle, a black-and-yellow fly which munches its way through the foliage. Squash the larvae and beetles by hand (very satisfying).

Harvesting asparagus
In the third year of growth, when the plants are sufficiently strong, cut the spears as they emerge for six weeks. It is traditional to stop harvesting in Ascot week, which is the third week in June. This gives the plants time to recuperate and develop full-grown foliage.