Mary Washington Asparagus

Asparagus is a perennial that can live for 15 or more years and will self-seed readily if you allow it to do so. Therefore, select a site carefully. It's going to be there for some time. Place your asparagus bed in a location that receives 8 or more hours of direct sunlight daily. Periods of 4-8 hours may be sufficient, however they will result in a lower yield. Asparagus prefers soil that is high in organic matter with a pH of 6.5 to 7.5. It does not tolerate clay soil, so if this describes your soil, consider creating a raised bed. Plants require high amounts of nitrogen and moderate amounts of phosphorus and potassium for optimal growth. Does best in zones 3-8.

Plant seeds indoors 3 months before last frost. Sow seeds 3/4" deep into pre-moistened seed starting media. Keep moist, but not wet, until germination has occurred. The ideal soil temperature for asparagus germination is 75-80 degrees (F) during the day and 65 degrees at night. Germination typically occurs in 14-21 days. Alternatively, seeds may be sown outdoors in mid-spring, around the time that apples are blooming. Sow seeds 2" apart and keep moist until germination has occurred.

After danger of frost has passed, transplant the seedlings into a W-shaped trench of roughly 8" at its deepest and 2" deep in the center. Place the seedlings in the center of the trench so that the roots go into the deepest parts of the trench. Space plants 8-14" apart in all directions. Mound up the soil around the stems as the spears grow, being careful not to bury any of the delicate ferns. Flowering may occur in the first year. If self-seeding is not desired, dig and remove the fruit-bearing female plants.

Insect Pests

The most damaging insect for asparagus is the asparagus beetle. Pesticides including pyrethrum can be effective when used regularly during the beetle stage. For those not wishing to use pesticides, trimming and burning ferns in the fall can help with prevention. Note, however, that cutting mature ferns in freezing climates can reduce the longevity of the plants as water can travel down the hollow stems and freeze out the crowns.

Diseases & Other Problems

Diseases are not usually a problem for open-pollinated asparagus varieties. The most common problem for asparagus is over-crowding and weeds. The former can be remedied by removing the seed-bearing, female plants. Weeds can be controlled by burning and/or shallow tilling in early spring (ensure that your plants are set deep enough to escape the tiller tines). Hand weeding is also an option. Many gardeners swear by adding salt to the bed every year, which will deter weeds while not bothering the asparagus.

Begin harvesting spears in the second year. As a general rule, no matter the age of the plants, harvest only spears that are larger than a pencil. The first flushes each season are typically the largest in diameter with subsequent flushes getting progressively smaller. Once spears are no longer large enough to be harvested, it's time to let the plants recharge for the next year.

CONSIDERATIONS:

Asparagus is a dioecious with male and female flowers being borne on separate plants. Pollination is usually performed by honeybees or other insects. The generally accepted isolation distance for maintaining varietal purity is two miles. Note that asparagus can be found growing in ditches in many parts of the country and may be a potential source for pollen contamination.

HARVESTING SEED:

Harvest berries from mature plants after they have turned red in color. Extract seeds by rubbing the berries on a screen or other rough material. Wash the seeds and dry where they are not in direct sunlight.

SEED LONGETIVITY:

Asparagus seeds will maintain at least 50% germination for five years when stored under ideal conditions.