Plant asparagus when the soil temperature reaches 50 degrees Fahrenheit in the spring, and avoid harvesting the plant during the first year. To prepare the garden bed for asparagus, remove all grasses and weeds from the intended garden bed, and plant the asparagus in a trench that is 6 inches deep. Apply phosphorus-rich fertilizer to the bottom of the trench before planting to encourage fast growth, and irrigate the plants only if the conditions are very dry.
After pouring the fertilizer into the bottom of the trench, place the asparagus crowns 18 inches apart on top of the fertilizer. Space rows of asparagus at least 5 feet apart to discourage disease. When covering the trenches, cover the asparagus crowns loosely, and expect to see new growth within one week.
When ferns emerge the first year, allow them to remain undisturbed through the winter, and treat for pests as needed. Cut the ferns to ground level at the beginning of the second spring.
Harvest asparagus beginning in the second year of growth by snapping the stalk at its base when it reaches 7 to 9 inches in height. At the end of the growing season, harvest all stalks, and apply a nitrogen-rich fertilizer to the soil surface.