How to Grow Asparagus

When to pick: Asparagus is a long-lived perennial, so readiness is measured in years and spear size rather than days from sowing. RHS: cut spears at no more than 18cm (7in) tall or about finger thickness; do not harvest for two years after planting crowns (three if grown from seed), then cut for six weeks from mid-April in year three and for eight weeks in subsequent years. Clemson: spears 6-8 inches are the best size for harvest and should be cut or snapped off at the soil surface before the tips begin to separate, after two to three full growing seasons before limited harvesting can begin.

Asparagus is planted as a dormant crown, not sown from seed, and it's the only true perennial vegetable most gardeners grow. That changes the timeline: RHS is clear that spears shouldn't be cut for the first two years after planting a crown (three years if you started from seed instead), and Clemson gives the same "two to three full growing seasons" figure independently. Every spear resisted in those early years becomes ferny top growth instead -- and that foliage is what builds up the crown's underground reserves for every harvest still to come.

From the third year, harvesting begins: cut spears for about six weeks from mid-spring, extending to eight weeks in every year after that. It's a genuinely long-term investment -- RHS puts a well-managed bed's productive life at around 20 years, though Clemson notes yields can start gradually declining after seven to eight, a real disagreement between the two sources that's recorded here rather than picked one way. Either figure means a bed planted now is still cropping well beyond a decade from today.