Asparagus is a surprisingly easy vegetable to grow. It is also a perennial plant, so you will have years of harvest from your original planting. Asparagus can be grown in California from either seed or crowns (roots). According to vegetable specialists at the University of California, Davis, planting crowns allows you to harvest your asparagus one year sooner than if you grow it from seed. It is important to prepare the planting bed in the fall, prior to the spring in which you will plant. Plant your asparagus crowns from January through March in all areas of California with the exception of the Imperial and Coachella valleys. Gardeners in these areas can plant as early as October.
Perform a soil pH test. This can be done yourself with an inexpensive testing kit you can purchase at most gardening centers. You can also take a soil sample to your county cooperative extension office to have it tested. Agriculturists at North Carolina University suggest that you take your soil sample from a depth of 12 inches.
Prepare the planting area. Use the results of your pH test as a guide to what type of amendments you will need. It's a good idea to add 2 to 3 inches of compost to the area. If the pH of the soil is below 6.0, you will need to add lime until it is within the range of 6.0 to 6.7. Follow the suggested application rate on the package.
Mix the amendments into the top 12 inches of soil, using the gardening fork. Allow the planting bed to sit over the winter.
Add 5 to 10 lbs. of 5-10-10 fertilizer for every 100 square feet of gardening area and work it into the soil.
Dig an 8-inch deep, 12-inch wide trench. Lay the crowns, end to end, 18 inches apart on the bottom of the trench, with the points up. Cover the crowns with 2 inches of soil. When the asparagus reach 8 inches in height, fill the trench the rest of the way.
Water the planting bed until the soil is moist, but not soggy. Keep the soil moist and the asparagus should sprout within two weeks.
Wait until the third year to harvest your asparagus. The first two years, allow the asparagus plants to go to fern, cut them to the ground when they turn brown and allow them to go dormant in the winter.