Carve a trench. As soon as the soil can be worked in spring, dig a trench about 12 inches deep and 12 to 18 inches wide. Leave 3 to 4 feet between each trench, if you have room for more than one.
Backfill with compost and soil. Put 4 inches of compost or well-rotted manure into the trench. Shovel in 2 inches of soil, and mix it with the compost. Then add bonemeal: 1 pound for every 20 square feet. The phosphorus in bonemeal strengthens the developing roots. Shovel in 1 more inch of soil and mix again. The trench should now be about 6 inches deep.
Mound the ground. Set the crowns about 18 inches apart in the trench. Mound the soil beneath each crown (as you would with a rose bush) and fan the roots evenly over the mounded soil. When all the crowns are in the trench, cover them with 2 to 3 inches of compost or rotted manure. Gently firm the soil, and water the trench. Leave the remaining soil where it is; as the stems grow you'll use it to fill around them.
Add more soil. When you see the top start to grow in 2 to 3 weeks, shovel about an inch of the reserved soil around the shoots. Keep adding soil as the shoots grow, about every week or so, until the trench is refilled.
Water and wait. Be sure your asparagus doesn't dry out through its first spring and summer. Water it when Mother Nature doesn't. Don't harvest any of the spears the first year. Think of asparagus like marriage: a long-term commitment that, with care, only gets better with time.
Maintain the mulch. Layer a half-inch of compost on the soil in spring and again in fall. Remember to keep the bed weed-free, but do not cultivate the soil because it might disturb the roots. A layer of shredded leaves or straw will help conserve moisture and keep weeds down.
Leave the ferns in fall. Once the stalks stop coming up, the tall, lacy ferns appear. They might look familiar; asparagus fern is a common houseplant, and a cousin of the vegetable. Don't cut the ferns down; they're collecting energy for next year's stalk growth. Let the foliage yellow and die back in the fall to protect the bed during the winter.
Remove them in spring. Diseases and the eggs of destructive insects can overwinter in the foliage, so remove it in the spring before new growth appears.