'Martha Washington' and 'Mary Washington' are the old standbys, but newer hybrids from Rutgers University and the University of California give higher yields, are more disease resistant, and can be harvested the second spring after planting.
Northern gardeners can try the Jersey hybrids, all-male varieties developed at Rutgers University. 'Jersey Knight' is longer-lived than some of the other Jersey hybrids and is tolerant of fusarium and resistant to rust. 'Jersey Giant' is more productive than 'Jersey Knight' in cold areas, such as Michigan, and is adaptable to a variety of growing conditions, while retaining good disease resistance.
The University of California (UC) hybrids are suitable for warmer, dryer climates. They grow enthusiastically from the southwest up to Washington State. These hybrids are not all male, however. The tips of 'UC72' stay tight in warm climates; 'UC157' spears are tinged with purple, and has higher yields than 'UC72.'
Think permanent. Choose the site carefully and your asparagus will grow there for years to come. Allow both vertical and horizontal space for the ferny leaves that asparagus grows after it's finished producing spears. The ferns can reach up to 5 feet tall, so plant where the foliage won't shade other plants that need sun.
Full or partial sun. Asparagus prefers full sun but—rare for the vegetable kingdom—it can take some shade.
No weeds. Asparagus doesn't compete well with weeds, so remove them all before you plant, mulch the bed well (with compost, rotted leaves or straw) and pull any weed that peeks through the mulch.
Check the soil. Asparagus enters into a long-term relationship with your soil, so make sure conditions are ideal before that first crown is planted. A soil test is the place to start. Asparagus is a heavy feeder, so the soil should be rich in organic matter to help make all the nutrients available to the roots. Compost is the best source of organic matter for your asparagus bed.
Good drainage. The soil must be well-drained so that it stays evenly moist, but never soggy. Poor drainage will cause the roots to rot. Sandy loam is best, with a pH of 6.5-7.5.