Asparagus is a perennial that may continue to produce edible sprouts, or spears, every spring for 20 years or more. Each asparagus plant is either male or female. The male plants produce more spears that are usually larger than those of female plants because the female plants use their energy to produce seeds. According to the University of Illinois Extension Office, new productive male hybrid varieties to look for are Jersey Giant, Jersey Knight, and Jersey Prince. Plant asparagus in early spring as soon as the ground can be worked.
Locate an area to plant your asparagus that receives at least six hours of sun each day and is in a location that will not be disturbed for several years. Opt for a location on the edge or back of the garden is preferred because the asparagus ferns get large, up to 6 feet tall, during the summer. Ensure weeds from the surrounding lawn cannot encroach into the asparagus bed.
Clear the area of all weeds and debris and rake smooth.
Dig a trench 6 inches deep and 12 inches wide for planting the asparagus crowns. If planting in rows, establish the rows 5 feet apart.
Add a 1-inch layer of compost to the trench and begin setting crowns, bud up, root down, into the trench 12 inches apart. Gently, so as not to break the roots, press down on the crowns so the bottom of the crown has contact with the loose soil and compost mixture.
Cover the crowns with a 2-inch layer of soil and add water until the soil and crowns are soaked.
Begin adding a mixture of half soil and half compost over the spears, once the first spears appear. Add a little at a time as the spears grow over the season until the trench is full.