Asparagus is a unique vegetable, functioning as a long-term perennial crop that can produce spears for 20 years or more from a single planting. Unlike annual vegetables, where placement is temporary, the initial decisions about site selection and spacing are permanent. A successful planting requires careful planning to ensure the crowns have the resources and space to thrive for decades, influencing the bed’s longevity and yield.
Preparing the Permanent Bed and Crown Depth
Selecting the proper site is the first step. Asparagus requires a location that receives full sun for at least six to eight hours daily and has well-draining soil. Asparagus roots are prone to rot in waterlogged conditions, so amending heavy soil with organic matter like compost or manure is necessary before planting. Once the site is prepared, planting begins by digging a trench typically 12 to 18 inches wide.
The depth of this trench should be between 6 and 8 inches for most home garden applications. A technique involves creating a small mound of soil or compost along the center of the trench bottom. This mound allows the asparagus crown to be placed with its roots spread out and draped over the sides.
Placing the crown over this central ridge ensures the roots are not bunched up and promotes outward growth, which is necessary for the plant’s stability and long-term storage capacity. Initially, the crown is covered with only about two inches of soil, leaving the trench partially unfilled. As the spears begin to grow, additional soil is gradually added to the trench throughout the first season until the entire trench is leveled out to the surrounding ground.
Essential Measurements for Plant and Row Spacing
The distance between the crowns within the row is referred to as in-row spacing, typically set between 12 and 18 inches. Planting crowns at the narrower end of this range, such as 12 inches, may result in a higher number of spears, but they may be slightly smaller in diameter. Using an 18-inch spacing provides more room for individual plants to develop a larger root system. This usually leads to thicker, higher-quality spears and a longer productive life for the bed.
The space between parallel rows is equally important. Row spacing is generally set between 4 and 5 feet apart, which allows for sufficient access during maintenance and harvesting. While some intensive methods suggest closer rows, a minimum of three feet between rows is recommended to prevent overcrowding as the mature plants, or ferns, grow large and wide.
A wider distance, such as 5 feet between rows, is often preferred because it accommodates equipment like wheelbarrows or tillers for weeding and allows for easy application of mulch. The difference between in-row and row spacing reflects the plant’s needs: close in-row proximity maximizes the use of the planting trench, while wide row spacing supports the plant’s mature size and maintenance requirements.
Spacing for Yield Longevity and Disease Prevention
Proper spacing is a direct defense against common asparagus diseases, which can shorten the productive life of the planting. The wide row spacing of 4 to 5 feet promotes good air circulation around the mature fern growth during the summer months. This air movement helps to quickly dry the foliage after rain or irrigation, creating an environment less favorable for the development and spread of fungal pathogens like Asparagus Rust or Cercospora blight.
Spacing also directly impacts the long-term yield by managing competition for limited resources. When plants are spaced too closely, their root systems compete more aggressively for water and essential soil nutrients. This increased competition stresses the crowns, leading to reduced spear size and potentially shortening the bed’s productive lifespan.
The generous spacing between plants and rows also simplifies maintenance tasks. Wider rows facilitate the application of mulch, which is necessary for weed suppression and moisture retention around the crowns. Furthermore, adequate row spacing ensures that workers can move through the bed during the harvest period without damaging the delicate ferns, which are responsible for photosynthesizing and storing the energy for the following season’s spear production.