Asparagus is a long-term investment, with plantings often remaining productive for 15 to 20 years, making the initial establishment steps particularly important. The most efficient way to begin an asparagus patch is by using crowns, which are the dormant, one-year-old root systems of the plant. Crowns provide a significant head start over planting seeds. While seeds are less expensive, crowns expedite the time to the first harvest by at least a year, establishing the robust root structure necessary for a perennial crop.
Preparing the Permanent Bed
Site selection is a foundational step because asparagus, once planted, is a permanent fixture in the garden for many years. The bed must receive full sun, ideally at least eight hours a day, and should be located where the tall, feathery ferns will not shade other garden vegetables. A well-drained soil environment is necessary, as asparagus crowns are highly susceptible to rot if they sit in standing water. If your soil is heavy clay, incorporating large amounts of compost, well-rotted manure, or other organic matter is essential to improve drainage and enrich the soil before planting.
The deep, perennial nature of the root system necessitates deep soil preparation, loosening the earth to a depth of 10 to 12 inches. Asparagus prefers a near-neutral to slightly alkaline soil pH, ranging between 6.5 and 7.0. It is beneficial to remove all perennial weeds, such as bindweed or quackgrass, before planting, as the crowns cannot compete well during their initial establishment phase. Once the bed is prepared, it is ready for the trenching method used to plant the crowns.
The Step-by-Step Planting Process
Planting the crowns begins by digging a trench, which should be about 12 inches wide. The depth typically ranges from 6 to 12 inches, depending on your soil type; 6 to 8 inches is preferable for heavier clay soils, while sandy soils can accommodate a deeper trench. The soil removed from the trench should be set aside, as it will be used gradually over the next few weeks to fill the trench completely.
Inside the base of the prepared trench, create small mounds or ridges of soil every 12 to 18 inches down the length of the row. A single dormant crown is then placed on top of each ridge, carefully draping the fleshy roots down and out over the sides of the mound. This specific placement ensures the roots are spread for optimal growth and the central bud, where the spears emerge, is slightly elevated.
The initial backfilling involves covering the crown with two to three inches of the reserved soil, firming it lightly, and watering thoroughly to settle the soil around the roots. As the young spears grow and reach four to six inches tall, more soil is gradually added to the trench, leaving the fern tips exposed. This gradual process continues until the trench is entirely filled and the crown is eventually buried about six to eight inches below the soil surface.
Initial Care and the First Harvest Rule
Newly planted crowns require consistent and even moisture, particularly during the first year, to encourage the development of a robust root system. Deep watering is recommended over frequent, shallow applications, as the goal is to encourage the roots to grow downward. Diligent weeding is necessary during this establishment period, as young asparagus plants struggle against competition for nutrients and water. Hand-pulling weeds is preferred over deep cultivation, which risks damaging the sensitive, shallow root buds of the crown.
The “First Harvest Rule” is the most important component of long-term asparagus success and requires patience from the gardener. All spears that emerge in the first year after planting must be allowed to grow unharvested, developing into tall, fern-like foliage. The ferns act as the “food factory,” using photosynthesis to produce and store energy in the underground crown, building the reserves necessary for future spear production.
A light harvest, lasting only one to two weeks, may be taken in the second year if the plants show exceptionally vigorous growth, though waiting until the third year is ideal for maximum production. Once the ferns yellow and die back in the late fall, they should be cut down to the ground. The bed can then be top-dressed with compost or a layer of mulch to prepare for the next spring.