Asparagus crowns are usually planted in trenches. Good preparation is important. In particular, remove all weeds before planting, as this is a permanent crop, and weeding will be difficult once growth has developed. Manure or garden compost should be dug into the area before planting.
Plant in trenches 30cm wide and 20cm deep. Make a ridge 10cm high along the centre of the trench. Place the asparagus crowns on the ridge, 30cm apart. Spread the roots evenly and fill in with soil so that the bud tips are just visible. Mulch the crowns with 5cm of well-rotted manure/garden compost. Leave 45cms between double rows and
stagger the plants. Paths between the beds should be 90cm wide. Don't overfeed this plant, as you'll encourage soft fern growth.
Jon