How to Grow Asparagus: Planting, Care, and Harvest

Asparagus is a long-term perennial crop that occupies a permanent bed and rewards patience with annual harvests of fresh spears for 20 years or more from a well-established planting. The patience requirement is real: most asparagus beds should not be harvested in their first two seasons, while the crown establishes and builds the energy reserves that fuel spear production in subsequent years. Understanding this upfront prevents the frustration of harvesting too early and compromising the bed’s long-term productivity.

Site and Soil Preparation

Asparagus performs best in deep, well-drained, slightly acidic to neutral soil with a pH of 6.5 to 7.0. It does not tolerate waterlogged conditions and will decline in wet soils. Because asparagus is a perennial that will occupy the same bed for two decades, thorough soil preparation before planting is worth the effort.

Remove all perennial weeds from the bed before planting, including roots: bindweed, couch grass, and dock competing with asparagus crowns through a permanent bed cannot be controlled without damaging the asparagus. Incorporate compost at 10 to 15 centimeters depth and check that drainage is adequate. Raised beds are an excellent option for asparagus in heavy clay soils.

Planting Asparagus Crowns

Asparagus is most commonly started from one-year-old crowns purchased bare-root in early spring. Crown planting gives a one to two year head start over seed sowing and is the standard approach for home gardens.

Dig planting trenches 30 centimeters wide and 20 to 25 centimeters deep, with 45 centimeters between trenches for multi-row beds. Create a central ridge of loose soil along the bottom of each trench. Place crowns on the ridge, spreading the roots down and outward over the mound like a spider’s legs, at 30 to 45 centimeter intervals along the trench. Cover with 5 centimeters of soil initially, then gradually fill the trench as shoots emerge through the season, which encourages deeper rooting.

Establishment and Care

In the first two seasons, allow all spears to develop into the full ferny foliage rather than harvesting. This foliage feeds the crown through photosynthesis, building the carbohydrate reserve that produces next year’s spears. In the second season, a very light harvest of the thickest spears for no more than two weeks is sometimes recommended, but restraint here pays off in subsequent years.

From the third season onward, harvest spears when they reach 15 to 20 centimeters tall, cutting or snapping them off at soil level. Harvest for 6 to 8 weeks in spring, then allow all subsequent spears to develop into foliage for the remainder of the season. Cut the yellowed foliage to the ground in autumn after it dies back.

Top-dress the asparagus bed with compost or well-rotted manure in autumn each year. Apply a balanced slow-release fertilizer in early spring before spears emerge.