The following sheet of information came from the establishment that sold us our asparagus (spring 2013). Not of all it is organic minded, but it includes helpful info.
Pendleton’s Country Market
1446 E. 1850 Rd., Lawrence, KS 66046 (785) 843-1409
Asparagus Growing Information
Highest yields are obtained in deep sandy well-drained soils, and heavy clay soils should be avoided. Deeply incorporated organic matter can enhance drainage in heavy soils.
Asparagus grows best at a pH of approximately 6.5 to7.5. The pH should be tested to a depth of 12 inches. lfthe pH is too acidic, lime should be incorporated.
Fertilizer and organic matter should be applied to the soil before plowing to establish a new planting. Adding 8 to 10 lbs. of a 5-10-5 fertilizer per 1,000 sq. ft. of garden area is suggested. If generous applications of organic matter is applied, use only half as much of 5-10-5 fertilizer.
Crowns should be planted while dormant. This can be as early as late winter. They should be planted when the ground is workable between frosts. As long as the crowns are covered with about 2 inches of soil, they are protected from any hard freezes. They can be planted until mid spring as long as plump, healthy roots are still available.
Quality one year old crowns are best. They are usually planted 12-15 inches apart in rows that are 4-5 feet apart. Six to 8 inches is the optimum depth for crown planting. Shallower
planting depths cause production of spindly, thin spears, while deep-planted crowns produce fewer spears of larger diameter.
After placement in the furrows or holes, the crowns are covered with 2-3 inches of soil. The furrow is gradually ﬁlled in as shoots emerge. By season’s end, the furrows should be entirely ﬁlled in.
Care of Asparagus
Established asparagus beds, with little care, will remain productive for many
years. But several practices need to be followed to insure successful crops.
It is important to control weeds in the planing. Weeds can be mechanically controlled with a hoe, cultivator, roto-tiller, etc… but tillage should not be deeper than 2 to 3 inches to avoid root damage. A variety of herbicides are registered for use on established asparagus. A popular one available for home gardeners is simazine (found in products such as Fertiloam’s Weed and Feed). Always consult individual herbicide labels for recommended application methods.
Tops should not be removed from asparagus plants until after killing freezes. The tops are essential in producing and transferring food to the roots for a vigorous crop the next spring. We recommend that if possible, leave the tops for winter mulch. This mulch will catch snow and protect the plants from severe cold, while adding moisture.
During the establishment years, fern growth, plant vigor, and health should be optimized with very careful cultural management. The Extension Service recommends a light harvest (2-3 weeks) during the first season after plant establishment. A full harvest season may follow the next year, however, if at any time the spear size is reduced to pencil size, the harvest should halt.
Asparagus harvest in Kansas normally starts about the middle of April and runs until the first of June. Spear growth depends on temperature. If it is warm, the asparagus may need to be harvested every three days; if hot, harvest is necessary every day. Harvest while the tips of the spears are still tight.
Spears should be hand harvested when 6-8 inches long. A knife can be used to cut the spears below the soil surface or they may be snapped at the soil surface. Cutting must be done carefully to avoid damaging the developing spears and the crown below the soil surface. The advantage to cutting spears is that if you are going to hold the asparagus for several days, the woody base restricts water loss, preserving the upper spear quality.
We recommend that most gardeners hand snap their
asparagus above the soil surface. Snapping severs the spear at
the junction between the green tender tissue generally above the
ground and the white woody tissue below ground. The advantage
to snapping is that you won’t injure unemerged spears and you
are getting a 100% edible product.
Beetles (1/4 inch long) have a red thorax and blue wings covered with yellow spots. Larvae and adults eat stems and leaves. Conspicuous dark eggs are laid on stems two to four generations per year. This is usually a problem in the spring on new stems. The Asparagus Beetle can be controlled by using rotenone, sevin, or malathion during the cutting season. We have never had enough of a problem with asparagus beetles in our
area to worry about them.
Rust first appears as small reddish—brown spots on stems. It may spread and cause leaves of young shoots to die and fall off. The UC 157 hybrid variety is rust resistant. In other varieties, rust can be controlled with a fungicide spray after harvest.
Fusarium Root Rot
Caused by the fungus Fusariurn, which is present in all regions of the United States. This disease enters the plant through young feeder roots, where it spreads and eventually
weakens and kills the plant. Infected plants wilt, tum yellow and are stunted. ln dissected roots, a reddish-brown color is positive diagnosis of ﬁisarium. Once fusarium is in the ﬁeld, there are no simple controls. New beds should never be planted in fields previously in asparagus.