Asparagus is a nutritious, cool-weather perennial vegetable that can take two to three years to harvest the first time. One plant produces vegetables for 12 to 15 years total though, so the initial wait for harvest can be well worth it. Asparagus requires well-drained soil and thrives well in most parts of Arizona.
Starting asparagus from seed takes the longest: You'll need to wait three full years before you can lightly harvest the spears. The best results come from planting healthy one-year crowns instead, because you'll be able to lightly harvest the following year.
Choose a sunny, well-draining spot for your asparagus garden bed. The plants can grow tall so you may need to space them far enough from smaller plants to avoid unwanted shade.
Prepare the asparagus bed early--the previous fall or winter if possible--by mixing plenty of organic material such as compost, manure, bonemeal, fireplace ashes and leaf mold. Mix the organic matter at least 6 to 12 inches into the garden bed soil.
Dig a trench 12- to 18-inches wide in the garden bed.
Mix the removed soil with more organic material and spread about 2 inches of the mixture into the bottom of the trench.
Create small mounds down the center of the trench, spaced about 15 to 18 inches apart.
Spread the roots of an asparagus crown over one of the mounds, and cover the roots and crown with soil. Repeat this process for each crown you are planting.
Tamp the soil down firmly on each crown and water if the soil is dry.
Every two weeks, pull 2 inches of soil over the tops of the crowns. Continue doing this until the trench is filled in.
Water the asparagus plantings when the soil is dry if there has been no rain.