NC STATE UNIVERSITY North Carolina Cooperative Extension Service
Durham County Center
721 Foster Street
Durham, North Carolina 27701
919-560-0525 Fax: 919-560-0530
www.ces.ncsu.edu/durham/
Urban Horticulture Note No. 15
ASPARAGUS
Asparagus will grow in any well-drained soil and, with proper bed preparation and summer care, the plants
should produce for 15 years or more. Therefore, since the crop will occupy the land for a long period of
time, you should start the bed properly: location, soil type, soil fertility, size and age of crowns, and correct
planting are important. Allow about 10 plants per family member.
Site: Select a sunny location, well-drained location for the bed. Soil should have a large amount of organic
matter tilled in, so that the tender spears can penetrate the soil. At the same time, till in lime and fertilizer as
indicated by a soil test. In the absence of a soil test, incorporate 3-5 lb. of 5-10-10 fertilizer per 100 square
feet of bed. The pH should be 6.0 - 6.7. Asparagus will not grow in very acid soil.
Variety: New Jersey hybrids are now recommended over old faithful Mary/Martha Washington. NJ hybrid
male plants are very productive, maintain vigor as they age, produce earlier, and can be harvested more
heavily. Two-year old crowns are desirable, but one-year crowns may be used.
A two-year evaluation trial of 14 cultivars at Whitethorne-Kentland Research Farm near Blacksburg,
Virginia, found the following results:
* Jersey Knight - best combination of spear size and yield
* Jersey General - good combination of spear size and yield
* Atlas - produced large spears and had the greatest yield
* UC 157 - large number of small spears
* Jersey Giant - very productive, but spear size was small in comparison
Viola 'Purple Passion' - unique appearance and distinctive, sweet flavor may enhance its potential
as novelty cultivars despite the lower yield potential.
To grow your own crowns: plant seed in spring 1/2" deep and 2" apart in rows 2-3' apart. Germination is
hastened by soaking in water 2-3 days before planting. Dig and transplant the seedlings the following
spring into the permanent bed.
When: Plant in fall or late winter after hard frost danger has passed but before plant growth begins.
Planting: Deep planting is no longer recommended. Dig a trench no deeper than 5-6" and wide enough so
that the root of the crown can be fully spread out. Set plants so that buds are pointing upward, and cover
with soil to ground level. Water well. The roots will spread horizontally rather than down, and in years to
come will produce a thick mat of roots and underground shoots. To allow for long-term future growth,
rows should be 5 feet apart.
Watering: Watering is extremely important any time there is a lack of adequate rainfall during the
growing season.
Fertilizer: Fertilize established beds twice each year (early March and at end of cutting season)
according to soil test results. In the absence of a soil test report, broadcast 2-5 pounds of 5-10-10
per 100 sq. ft. of bed area at each application.
North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure
equal opportunity regardless of race, color, creed, national origin, religion, sex, age, or disability. In addition, the two
Universities welcome all persons without regard to sexual orientation. North Carolina State University, North Carolina A&T
State University, U.S. Department of Agriculture, and local governments cooperating.
Maintenance: Weeds are the biggest problem of asparagus culture, since they offer a great deal of
competition for the developing shoots. Be diligent about weed control as the bed can quickly be
overtaken, to the detriment of the asparagus. Cultivation must be very shallow since the roots are
near the surface. Two inches of light mulch will discourage weeds and help conserve moisture.
Contact the County Extension Center for suggestions on chemical control methods.
Allow spears to grow until after frost has turned them brown. During the summer, the ferny top
growth is producing food for the shoots below. When the fern has been turned brown by frost, cut it
down and destroy it. Cutting the fern before natural withering will reduce next year's crop.
Harvesting: No harvesting should be done during first growing season. Recent research has shown
that harvesting shallow- planted asparagus after the first year boosts yields 40% over three years.
Thereafter harvesting may be done from 6-8 weeks per year. Weak or small spears result from
harvesting too extensively and not allowing sufficient fern to develop to produce food for the next
year. Snap spears off at ground level or exercise care when cutting so as not to damage spears which
have not yet emerged.
Storage: Asparagus loses quality and fiber develops rapidly after harvest. Wash and cool the
asparagus soon after harvest. If asparagus wilts, it can be made turgid by soaking in water.
Prepared by: Durham County Master Gardener Volunteer Program Revised:
October 26,2007
North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure
equal opportunity regardless of race, color, creed, national origin, religion, sex, age, or disability. In addition, the two
Universities welcome all persons without regard to sexual orientation. North Carolina State University, North Carolina A&T
State University, U.S. Department of Agriculture, and local governments cooperating.