Asparagus is a highly anticipated perennial vegetable, valued for its distinct flavor and early spring appearance. Establishing an asparagus patch takes a few years before significant harvesting. Once established, a well-maintained bed can produce for 15 to 30 years, offering a consistent bounty of tender spears.
Growing Asparagus
Site Selection and Soil Preparation
Selecting an appropriate site is important for a successful asparagus bed. Asparagus plants thrive in full sun, requiring six to eight hours of direct sunlight daily. Placing the bed at the northern edge of a garden prevents the tall asparagus ferns from shading other plants. Well-drained soil is also important, as roots are susceptible to rot in waterlogged conditions. For heavy clay, raised beds improve drainage.
Asparagus prefers a soil pH between 6.5 and 7.5, which is slightly acidic to neutral. Conduct a soil test before planting to determine nutrient levels and pH for amendments. Before planting, prepare the bed by loosening the soil to a depth of 12 to 18 inches and incorporating organic matter, such as compost or well-rotted manure, to enhance fertility and drainage. Remove all perennial weeds from the planting area, as asparagus struggles with competition, especially during establishment.
Planting Asparagus
Asparagus is grown from one-year-old crowns, planted in early spring, two to four weeks before the last expected frost. Dig a trench 6 to 8 inches deep and 12 to 18 inches wide. Create a 2 to 4-inch high mound at the trench bottom, spreading crown roots evenly over it. Space individual crowns 12 to 18 inches apart within the trench, with rows 3 to 5 feet apart.
After placing the crowns, cover them with 2 to 3 inches of soil. As spears grow throughout the first season, gradually add more soil to the trench, being careful not to completely bury emerging spears, until the trench is filled to ground level. This gradual backfilling encourages stronger root development. Water newly planted crowns consistently for establishment.
Ongoing Care
Newly planted asparagus needs consistent moisture, especially during its first two years, requiring one to two inches of water per week if rainfall is insufficient. Once established, asparagus becomes more drought-tolerant, but still benefits from watering during dry spells. Effective weed control is important; asparagus has a shallow root system that competes poorly with weeds. Hand-weeding is the preferred method to avoid damaging delicate crowns. Applying a 3 to 4-inch layer of organic mulch (e.g., straw or compost) helps suppress weeds and retain soil moisture.
Asparagus plants are moderately heavy feeders. After the first year, an annual application of a balanced fertilizer (e.g., 10-10-10 blend) is beneficial in early spring before spears emerge or after harvest. Allowing spears to “fern out” into tall, feathery foliage after harvest is important. This fern growth allows the plant to photosynthesize and store energy in its crowns for next year. Leave ferns until they naturally die back and turn brown in late fall or early winter.
Harvesting Asparagus
First significant asparagus harvest occurs in the second or third year after planting crowns. Harvesting too early can weaken the plant and reduce its long-term productivity. In the first harvest year, pick spears for only a short period (a week or two) to allow the plant to continue building strength.
Harvest spears when they are 6 to 10 inches tall and pencil-thickness in diameter, before tips begin to open. Thinner spears are more tender. Harvest by snapping spears off cleanly at or just below the soil line, or by cutting with a sharp knife. The harvest season lasts 6 to 8 weeks, typically May through June, varying by climate and plant vigor. Stop harvesting when spear diameter decreases to pencil size, or when the plant shows signs of slowing growth, to ensure crowns store enough energy for next year.
Storing Asparagus
Asparagus spears lose freshness quickly after harvest. For short-term storage, keep them fresh in the refrigerator for up to a week. A common method involves placing spears upright in a jar or glass with an inch of water at the bottom, similar to a bouquet of flowers.
Covering the jar loosely with a plastic bag helps maintain humidity around the spears, extending freshness. For longer preservation, asparagus can be blanched and then frozen. Blanching involves briefly immersing spears in boiling water followed by an ice bath, which helps retain color, texture, and nutrients before freezing. This allows for storage for several months, extending enjoyment beyond its spring season.
Nutritional Benefits and Culinary Uses
Asparagus is a nutrient-dense vegetable with various health benefits. It is a good source of vitamins (K, A, C, folate), essential minerals, and dietary fiber, contributing to digestive health.
Beyond its nutritional value, asparagus is versatile in the kitchen. Its distinct, slightly earthy flavor complements a wide range of dishes. Asparagus spears can be roasted, grilled, steamed, or stir-fried. They make an excellent side dish, can be incorporated into salads, quiches, and pasta, or enjoyed simply with seasoning.