Gardening Note # 2

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 sf 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:

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' 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: 1) about March 1-15 (before spears start to grow), broadcast over the bed 2-5 lbs of 5-10-10 per 100 sf bed area. 2) Repeat the application at the end of the cutting season.

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. 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 asparagus soon after harvest. If asparagus wilts, it can be made turgid by soaking in water.

Gardening Notes Index Page Return to Master Gardener Page
This information compiled by Cumberland County Master Gardeners.
This page was created using the Durham Master Gardener Homepage as a model. Our thanks to them and especially to Pauline Marx, Pam Reading and Eileen Lowenbach.
This page was revised on 05/11/98