Asparagus is a perennial plant that is harvested as a vegetable crop. The plant grows to a height of 5 feet and will produce edible spears for up to 15 years. One asparagus plant will produce a half-pound of vitamin-rich vegetable spears each year once it becomes established. Plant asparagus on the north side of a garden to maximize the amount of light the plant receives. Asparagus should not be harvested until it reaches two to three years of age, as this will strengthen the crown to increase production.
Purchase 1-year-old asparagus crowns. Inspect the plants to make sure they are healthy and do not present signs of disease.
Plant asparagus in late spring once the soil has warmed to 50 degrees F. Planting the crown earlier puts the plant at risk for rotting as the ground is cold and wet. Add 3 inches of organic compost to the planting area and use a tiller to work the soil to a depth of 12 inches.
Test the soil with a soil pH test kit. Add limestone to the soil if the pH is less than 6.0. Rake the soil to work the limestone several inches in.
Dig a furrow to a width of 6 inches and depth of 12 inches. Space the rows 3 feet apart. Create a small mound in the furrow to spread the crown roots over. Apply 1 pound of a super phosphate fertilizer (0-20-0) to the bottom of the furrow for every 50 feet.
Place the crowns on top of the fertilizer at a spacing of 1 1/2 feet apart. Crowns placed too close together are more prone to fungal disease due to poor air circulation.
Fill the furrow with soil, making sure the crown has at least 6 inches of soil on top of it. Gently fill the soil around the crowns and do not pack in place, as this will slow the emergence of the asparagus spears.
Water the asparagus crowns after planting to moisten the soil. Asparagus is drought-resistant and does not require a regular water application except during periods of drought.
Allow the spears to grow the first year without harvesting them. This will increase the crown growth for a strong spear production the following year.