How do I plant an asparagus bed, and when can I start cutting?

Asparagus is the longest commitment in the vegetable garden. A well-made bed produces for fifteen to twenty years or more, and a badly sited one is a permanent nuisance you eventually dig out. Almost all the work that decides the outcome happens before the crowns go in the ground.

Step by step

1. Choose a permanent, sunny, sheltered position.The bed will be there for two decades, so put it somewhere it will not be in the way, will not be dug through, and gets full sun. Asparagus will not tolerate shade.
2. Check the drainage honestly.Asparagus dies in wet soil. If the site puddles in winter, either drain it or build a raised bed 20–30cm above the surrounding ground. This is the single most common cause of a bed that fails.
3. Clear every perennial weed first.You will never be able to dig this bed out again. Couch grass, bindweed, ground elder and creeping buttercup must be gone completely before planting — take a full season over it if that is what it needs.
4. Improve the soil deeply.Dig in generous amounts of well-rotted organic matter to a good depth. Asparagus is deep-rooted and this is the only chance you get to work the soil.
5. Buy one-year-old crowns from a reputable supplier.One-year crowns establish better than older ones despite looking less impressive. Modern all-male F1 varieties are far more productive than old types because they put nothing into seed. Plant the day they arrive if you can; keep the roots damp if you cannot.
6. Plant on a ridge in a trench.Take out a trench about 30cm wide and 20cm deep, make a low ridge of soil down the centre, sit each crown on the ridge with the roots spread down both sides, and cover with about 5–8cm of soil. Space crowns about 30–45cm apart, rows 45cm apart.
7. Fill the trench gradually as the spears grow.Draw soil in over the first season until the trench is level with the surrounding bed. It anchors the crowns and gets them to the right depth without burying the new growth.
8. Cut nothing in the first year after planting.This is the discipline that decides how long the bed lives. Every spear left to grow into fern builds the crown. Cutting in year one permanently weakens the plant.
9. Cut lightly in the second year, normally from the third.In year two take a few spears over two or three weeks. From year three cut normally — spears at about 15–20cm, cut at or just below soil level with a knife.
10. Stop cutting by midsummer, every year.The traditional cut-off is around the longest day, or a little after in an established bed. After that, everything is left to grow into fern, which rebuilds the crown for next spring. Cutting into July and August is how people kill a productive bed.
11. Let the fern stand, then cut it down in autumn.Leave the fern until it yellows in autumn, then cut it to about 5cm and clear it away. Mulch the bed with compost or well-rotted manure over winter.

Tips

• Growing from seed is cheaper and works, but adds a year before you can cut anything and gives a mix of male and female plants. Crowns are the sensible route for most gardens.
• Female plants produce berries and self-sown seedlings that become weeds in the bed. All-male varieties avoid it and yield better.
• Never dig or fork the bed. Crowns sit near the surface and are easily damaged. Weed by hand or with a very shallow hoe.
• Asparagus beetle — black and yellow, with grey grubs — strips the fern in summer and weakens the crowns. Pick them off by hand.
• Salt was traditionally spread on asparagus beds as a weedkiller. Do not do it — it damages soil structure and it is not what the plant needs.

Common mistakes

• Cutting spears in the first year — The crown has not built any reserves. Cutting in year one is the most common reason a bed never becomes productive.
• Planting into ground that has not been cleared of perennial weeds — You cannot dig out couch grass or bindweed later without destroying the crowns. It is the mistake there is no recovery from.
• Cutting into midsummer because the spears keep coming — The plant needs the second half of the season to rebuild. Cutting past the traditional cut-off shortens the life of the bed sharply.
• Planting on wet ground — The crowns rot. If the site is wet, raise the bed rather than hoping.

Keeping on top of it

• Weed by hand — never hoe deeply, the crowns are shallow (regularly through the growing season)
• Mulch with compost or well-rotted manure (annually, in late autumn or early spring)
• Cut down yellowed fern and clear it (annually, in autumn)
• Check for asparagus beetle on the fern (weekly through summer)

Questions people ask