Asparagus is not only delicious, it is extremely long-lived--an asparagus bed can last over a century. That's permaculture! Provide good drainage, mulch yearly to keep weeds down, and enjoy the luxury of asparagus for a month or two every spring. Plants must size up and get a good root system before they can stand harvesting. There's not much else to it except patience.Plant on cutting your first crop the 3rd year. (My hard-won advice on this score: Do it now. If you put it off, in three years you still won't have asparagus.) Heirloom Mary Washington strain from 1919, bred for uniform thickness and freedom from rust disease.
Site a bed where it has good drainage and warms up fairly early in spring. In hot-summer climates, the east side of deciduous trees is great--sun comes through the bare branches for an early warm-up in spring, there is afternoon shade is summer, and the trees automatically mulch your asparagus bed. Cooler areas will want to have full sun all year. Good drainage is key. If you have heavy clay or live in a very rainy climate, be sure to add lots of compost and some rocks under the plants. Mulch is also key, to keep grass and weeds from invading the beds and weakening the plants. All that can wait, though, because these perennials are often started in pots for the first year.