   Growing Asparagus - January 31, 2001 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Asparagus is a perennial vegetable that thrives with little care and can produce an early spring harvest of fresh succulent spears. Asparagus prefers well-drained, sandy loam soil and comes back each year from underground storage roots and rhizomes. It requires full sun and is most successful when it can have a dormant "rest" period of either cooler weather or dry soil. For some, asparagus is an acquired taste. However, if you have a backyard garden, asparagus is an interesting crop that is usually very expensive at the supermarket. Most backyard gardeners plant asparagus crowns. The nursery industry grades the crowns as "1-year", "2-year", and "3-year" from smallest to largest. In reality, all are one year-old crowns grown from seed. Larger crowns have greater vigor and are preferred. It is virtually impossible to buy commercial crowns that are free of Fusarium root rot. If you have had serious Fusarium problems in your garden, then plant asparagus from disease-free seed. It will take an extra year, but maybe you aren't in a hurry anyway. Buy crowns or seed from a reputable nursery or seed catalog. Plants get big and gangly (5-6 feet tall), so plant them on the north or east side of your garden to avoid shading other low-growing crops. Plant after the soil has reached 50 degrees F. Seeds can be sown 1 inch deep, 3 to 4 seeds per established plant desired and then transplanted the following year to the desired density. Dig a 6-inch trench in well-tilled soil. Phosphorus fertilizer should be liberally applied in the bottom of the trench. This ensures it will be available in the root zone. Phosphorus will help ensure vigorous root growth. Crowns should be spaced 1 foot apart in rows. Each row should be 4 to 5 feet apart. Crowns should have buds facing up and root systems spread out as much as possible. Cover the crowns with loose soil up to the original soil level. Do not harvest during the first year. Instead, allow the plants to grow wildly and keep them well watered. This will allow them to photosynthesize at maximum potential and store that energy in the crowns for the following year's crop. The following spring before asparagus emerges, remove the brushy, dead tops, weed the area, and fertilize with 1.2 pounds of 5-10-10 fertilizer per 100 square feet of bed. If you are tempted, only harvest a few spears the second year allowing the rest to grow. Sidedress that same amount of fertilizer again in July. The third spring, you may start harvesting spears after they reach 7 to 10 inches in length. Simply snap then off leaving the tough stub on the plant. The spear should be green and tender. There is a "2-4-6 rule" for harvesting asparagus. Harvest for two weeks the third year, four weeks the fourth year, six weeks the fifth and each subsequent year. Spears will keep for several days if washed, make a clean cut on the end, place the spears in water, and immediately refrigerate them. At full production, one 40-foot row of asparagus should yield 10 to 25 pounds of spears per season. Asparagus plants are dioecious, meaning they produce male and female flowers on separate plants. The seedlings produced by these plants can sometimes become a weed problem. Newer varieties are all-male hybrids that do not produce seed. The most common open pollinated variety is Mary and Martha Washington. All male hybrid varieties are: Jersey Giant, Jersey Knight, and Jersey King. Whatever variety you plant, know that asparagus contains more folic acid than any other vegetable and high in fiber, potassium, thiamine, vitamins A, C and B6, and glutathione, a powerful antioxidant. Finally, we have the age-old question about why eating asparagus can result in odd smelling urine (rotten cabbage, ammonia, etc). Biochemists have isolated sulfur-containing compounds including, but not limited to methyl mercaptan. These odd smelling compounds are likely to be caused by the breakdown of asparagusic acid: a compound unique to asparagus. Then why does it affect some people and not others? The answer is in our genetics. The trait of producing smelly urine after eating asparagus is an inherited trait. The University of Arizona Cooperative Extension has publications and information on horticulture and gardening. Come and join me for an upcoming fruit tree pruning demonstration February 3, 17, and March 3. and don't forget about the upcoming Camp Verde Pecan and Wine Festival on February 10.If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@kachina.net and be sure to include your address and phone number. The Yavapai County Cooperative Extension web site is http://ag.arizona.edu/yavapai/. |