To my surprise, I learned a few years back that asparagus is an amazing desert plant. It needs hardly any water over winter (I deep water it maybe once a month, letting the hose trickle on it for a few hours until I remember to turn it off). Then in late winter, about the beginning of February, I tear out the dried asparagus ferns left in since last year to keep weeds down (and let the cats have a play area). Then I deep water one more time and wait for the new spears to appear. When the spears begin appearing, I water abut once per week.
Asparagus has been the easiest plant for me to grow. It's amazing how expensive it is when it's so easy to grow. It also doesn't have to be replanted for twenty or thirty years! How great is that? You do have to make sure the spears don't get overcrowded and put some more dirt on the beds every few years, as the plant migrates closer to the surface each year.
This year, 2012, I'm planting more asparagus by seed rather than by the actual asparagus plant. I'm doing it for two main reasons: 1) because I'm cheap and a bag of 75 asparagus seeds costs $2 rather than $2 per plant. 2) because you get a wider variety of selection with seeds, for example, I'm planting the old heirloom variety called Precoce D'Argenteuil, a gourmet variety that is supposed to be "highly esteemed in Europe for its delicious stems with rose-colored buds that can be blanched white."
There's actually a third reason, which is that if you plant seeds and then harvest the plant's seeds, plant them again, harvest them, plant them again, ad nauseam, then eventually you will breed your own variety of plant which is adapted to its environment. For example, the initial seeds of Precoce D'Argenteuil that I purchased came from Baker Creek Heirloom seeds in Minnesota. Even though the Precoce D'Argenteuil asparagus is originally Italian, these plants are at least somewhat adapted to Minnesota because they were raised there.
It's really important to raise your own plants to get ones that grow perfectly in your personal garden. What does it matter to me if these asparagus thrive in Minnesota? I'm in the desert!
Asparagus
Plant Family
Miscellaneous
Soil
Fertile, well drained, and free of persistent weeds.
Position
Full sun to partial afternoon shade.
Frost tolerant
Long-lived hardy perennial. Beds can produce for decades.
Feeding
Mulch with 2 inches of rich compost or rotted manure every winter.
Spacing
Single Plants: 1' 6" (45cm) each way (minimum)
Rows: 1' 6" (45cm) with 1' 6" (45cm) row gap (minimum)
Sow and Plant
Set out dormant 1-year old roots, called crowns, in late winter or early spring. A few varieties can be grown from seed.
Notes
After the stems die back in early winter, cut them off at ground level and compost them. Remove weeds, apply compost and mulch, and your yearly maintenance is done.
Harvesting
Begin gathering spears the second year after planting, cutting all spears that appear for a month in early spring. In subsequent years, harvest for 6 weeks each spring.
Troubleshooting
Cutting new shoots just below the surface often helps control problems with asparagus beetles, which often lay their eggs on tender shoots near the soil line.