Asparagus is a perennial vegetable grown from dormant root masses called crowns. Establishing an asparagus bed is a long-term gardening investment, as a well-maintained patch can produce fresh spears for 20 years or more. This effort ensures a delicious, annual harvest that begins early in the spring season.
Preparing the Permanent Asparagus Bed
Selecting the appropriate site is the first step toward a successful, long-lived asparagus patch. The location must receive full, direct sunlight for at least six to eight hours each day. Since asparagus develops deep, extensive root systems, the soil must offer excellent drainage to prevent the crowns from rotting. If the native soil is heavy clay, building a raised bed is a practical solution.
Soil preparation requires deep working to accommodate the perennial roots. The planting area should be tilled or dug to a depth of 12 to 15 inches to loosen the subsoil. Incorporate aged manure or rich compost to improve fertility and structure. Asparagus thrives in soil that is slightly acidic to neutral, with an optimal pH range between 6.5 and 7.5.
Planting Asparagus Crowns
Asparagus is typically planted in early spring, three to four weeks before the last expected frost date, using one-year-old dormant crowns. Begin by digging a trench 6 to 8 inches deep and 12 to 18 inches wide. If planting multiple rows, space the trenches about three feet apart.
Create a small, two-inch-high mound of soil down the center of the trench. Place the crowns on top of this ridge, spacing them 12 to 18 inches apart, and drape the fleshy roots down the sides. The crown’s central growing point should face upward. Immediately cover the crowns with two to three inches of the excavated soil.
The remaining trench is filled gradually as the plant grows. As new spears emerge and grow a few inches tall, add another two inches of soil to the trench, taking care not to completely bury the shoots. Continue backfilling over the course of the first growing season until the trench is level with the surrounding ground. This technique encourages a strong, extensive root system.
First Year Establishment and Care
The primary goal of the first year is establishing a robust crown and root system, which requires consistent care. The bed needs a steady supply of moisture, receiving about one to two inches of water per week, especially during dry periods. Hand-weeding is important, as young plants struggle to compete with weeds for water and nutrients.
Weeding should be done carefully and shallowly, avoiding deep cultivation that could damage the sensitive roots. Allowing the plant to grow its full, feathery “ferns” is necessary for future production. These ferns photosynthesize energy, which is transferred down to the crown for storage, fueling the next year’s spear production.
Do not cut the ferns back while they are green, as this depletes the crown’s energy reserves. Once the foliage naturally dies back and turns yellow or brown in late fall or early winter, cut the dead ferns down to the ground. Applying a layer of compost or aged manure at this time helps insulate the bed and provides nutrients for the following spring.
The Waiting Game When to Harvest
Patience is required when growing asparagus, as the first significant harvest does not occur until the third year after planting crowns. This waiting period ensures the crown develops enough stored energy to support years of future harvesting. Harvesting in the first year can severely stress or kill young plants by removing the energy-producing ferns.
During the second year, you may take a very light harvest for only one or two weeks if the plants look vigorous. The first full harvest season begins in the third year, allowing you to pick spears for six to eight weeks. Harvest spears when they are six to ten inches tall and about the diameter of an index finger. Spears can be harvested by snapping them off cleanly at the soil surface or by cutting them with a sharp knife one inch above the ground.