Asparagus

Soil requirements
Asparagus grows in most any soil as long as it has good internal drainage. Asparagus roots do not like waterlogged soils that will lead to root rot. It prefers a soil pH of 6.5-7.5., and will not do well if the pH is less than 6.0. Have the soil tested to determine phosphorus and potassium needs; or add 20 lbs of a 10-20-10 or similar analysis fertilizer per 1,000 square feet, tilled to a 6 inch depth before planting.

Planting
Asparagus can be planted from seed. However, caring for the small seedlings until they become established can be time consuming. Also, because the seeds are spaced a few inches apart, the crowns will have to be dug and transplanted to their permanent, wider-spaced location in the garden after one year. Thus, one year of potential spear production is lost due to transplanting.

Select the new all-male hybrid asparagus varieties such as Jersey Giant, Jersey Prince, and Jersey Knight. These varieties produce spears only on male plants. Seeds produced on female plants fall to the ground and become a seedling weed problem in the garden. Female plants also have to expend more energy to produce the seeds that decreases the yields of asparagus spears on female plants. The all-male hybrids out-yield the old Mary Washington varieties by 3 to 1.

Asparagus can be planted after the soil has warmed up to about 50 degrees F. They will not grow until the soil warms and there is danger of the plants being more susceptible to rot if crowns are exposed to cold, wet soils over a prolonged period. Plant the asparagus so that it will not shade the other vegetables and will not be injured when the rest of the garden is tilled.

Dig a furrow no deeper than 5 to 6 inches. The deeper asparagus crowns are planted, the more the total yield is reduced. Apply about 1 lb. of 0-46-0 (triple superphosphate) or 2 lbs. of 0-20-0 (superphosphate) fertilizer per 50 feet of row in the bottom of the furrow before planting. This will make phosphorus immediately available to the crowns. Omitting this procedure will result in decreased yields and the spear production will not be as vigorous.

Toss the crowns into the furrow on top of the fertilizer. The fertilizer will not burn the crowns, and the plants will grow regardless of how they land so don't bother to spread the roots. Space the crowns 1-1/2 feet apart in the row. If more than one row is planted, space the rows five feet apart from center to center. Wide between-row spacing is necessary because the vigorously growing fern will fill in the space quickly. Wide spacing also promotes rapid drying of the fern to help prevent the onset of fungus diseases.

After planting, back fill the furrow to its original soil level. Do not compact the soil over the newly filled furrow or the emergence of the asparagus will be severely reduced. Spears should emerge within one week in moist soils.

Do not harvest the asparagus during the planting year. Spears will be produced from expanded buds on the crown. As the spears elongate and reach a height of about 8 to 9 inches, the tips will open. The spear will become woody to support the small branch lets that become ferns. The ferns produce food for the plant and then move it down to the crown for next year's spear production.
width="180" height="135">Asparagus

Harvesting
Harvest asparagus by snapping 7 to 9 inch spears with tight tips. There is no need to cut asparagus below the soil with a knife. This may injure other buds on the crown that will send up new spears. The small stub that is left in the soil after snapping, dries up and disintegrates. A new spear does not come up at the same spot, but comes up from another bud that enlarges on another part of the crown.

As the tips of the spears start to loosen, fiber begins to develop at the base of the spears, causing them to become tough. The diameter of the spear has no bearing on its toughness. When harvesting, the asparagus patch should be picked clean, never allowing any spears to fern out, as this gives asparagus beetles an excellent site to lay their eggs.

The year after planting, asparagus can be harvested several times throughout a three-week period, depending on air temperatures. Harvesting the year after planting will stimulate more bud production on the crown and provide greater yields in future years, as compared with waiting two years before harvesting.

Asparagus spears will start to emerge when the soil temperature reaches 50 degrees F. After this, growth of asparagus is dependent on air temperature. Early in the season, 7 to 9 inch spears might be harvested every 2 to 4 days. As air temperatures increase, harvesting frequencies will increase to once or twice per day, harvesting 5 to 7 inch spears before the tips start to fern out and lose quality. The second year after planting, the length of harvest can increase to about 4 to 6 weeks. The third year after planting and thereafter, harvesting can continue for 6 to 8 weeks. Since the length of harvest season will vary from year-to-year depending on air temperature, stop the harvest when the diameter of 3/4 of the spears becomes small (less then 3/8 inch). Experience gained by growing the crop will make it easier for the gardener to know when to discontinue the harvest.

When harvest is finished, snap all the spears off at ground level. Apply 1/2 lb. of ammonium nitrate fertilizer per 50 feet of row . At this time, a home garden formulation of glyphosate non-selective herbicide (such as Roundup) can be sprayed on the asparagus patch. This will kill any existing weeds. New spears will then emerge, fern out, and provide a large canopy to cover the space between the rows. Once a dense fern canopy is formed, weed growth will be shaded out.

Storage
Asparagus is very perishable and should be harvested in the morning when air temperatures are cool. After picking, immerse the spears in ice-cold water to remove the heat; then drain the water and place the spears in plastic bags. Store in the refrigerator at 38 to 40 degrees F. Asparagus will keep for 1 to 2 weeks with little loss of quality.