To plant asparagus roots, combine both compost and fertilizer with general garden soil, and form a mound. Then, set an asparagus crown on top of the mound, and gently lay the roots down the sides. Set the crown roughly 6 inches below the surface, then cover the roots with soil all the way back up to the crown.
Preparing the planting area is just as important as the planting process itself. You must ensure that the area is free of all weeds and grasses, which may take some time -- up to one full year in some cases. Domesticated asparagus cannot survive with competition from weeds and grasses.
When the area is cleared, dig a 1-foot deep by 1-foot wide trench. The asparagus must be planted at roughly 18-inch markers, so in preparation for planting, it's best to start with a trough full of compost and fertilizer every 18 inches. Once it is planted, water the asparagus thoroughly, and when shoots begin sprouting, continue to add soil until the trench is level with the surface.
Once the asparagus is thriving, weed carefully and frequently for the first few years, and do not plant other vegetables in the same bed. Additionally, within the first year of planting, harvest only a few spears from each plant, and only for a period of two weeks. The following year, you may harvest for three weeks. Asparagus takes time to build a strong root system.