Water

• Asparagus needs thorough watering during the first growing season.  While the crowns are getting established, plants should be watered weekly until the soil is moistened to about 8- 10 inches. Once established, plants can tolerate some drought but need water during long, dry periods when they should get 1-2 inches of water per week.
• Do not overwater to prevent water-logged soil. If possible, use drip irrigation to prevent disease from getting established on wet foliage.

• Buds should appear in 10-12 days once the soil temperature is above 45-50 degrees. Do not harvest spears for the first or second year after planting. Allowing the spears to grow into ferns during these two years will help the plant store nutrients in the roots that are necessary for the following year's growth.
• Harvest spears when they are about 6-8 inches tall and about as thick as a little finger. Choose spears when heads are tight. Cut or snap off the spears at ground level. During the first harvest year, take spears for only 2 weeks then allow ferns to develop. After that first harvest, cut spears for about 6-8 weeks, until about mid-July at the latest.
• After harvest and in preparation for winter, ferns can be cut down to about 2 inches and covered with mulch, chopped leaves or straw. This will help deter early spring weeds and add some nutrients. See the fertilizer section for post-harvest recommendations.

Common Insect Pests

Asparagus Beetle: there are 2 types of asparagus beetle – the common (CAB) and the spotted (SAB). Both cause browning and scarring as they feed on the stalks. The common type is found more often and causes more damage to the plant since the larvae and adults also eat the ferns. If significantly defoliated, the plant will be weakened and will not provide enough nutrients for the growing spears during the next growing season. Damaged plants are also more susceptible to fungal infection.

The Common Asparagus Beetle is about 1/4 - 3/8 inch long. The head, legs and body underside are smooth, shiny blue-black. The wings have 3 large, whitish spots on each wing cover, with a red outline.

• Eggs are deposited in rows along the stalk in groups of 3-10 and are usually dark brown. Eggs hatch within a week of deposition and move to the stalks and ferns to start feeding.
• Larvae are wrinkled, have a slightly humped back, with a grey, brown or black head and legs. They go through 4 stages of growth as they feed for about a week until maturity, fall to the ground and pupate in the soil.
• Adults emerge in about 7 days to start another generation. The adults feed on ferns until September when they look for loose tree bark or hollow stems of asparagus plants to overwinter. They emerge in the spring as new spears are appearing.

The Spotted Asparagus Beetles (SAB) adults differ in several ways from the common asparagus beetle. The spotted variety is about 3/8 inches long and is tan to orange with 6 black spots on each wing cover. SAB adults will feed only on the spears but will lay their eggs on the ferns and then the larvae will feed on the berries of the female plants. The adults emerge in May, later than the common asparagus beetle. Adults will chew on young spears, making them unsuitable for sale. They will have 2-3 generations per year. When present, monitor and manage them as for the common asparagus beetle.
Monitoring should begin as soon as the spears begin to emerge.  Look for them in the afternoon when they are active. Remove any eggs by hand, dropping them, larvae and adults into a container of soapy water. Practice regular monitoring since new adults can fly into the garden.  Harvest spears every day to prevent any eggs from hatching and to reduce feeding sites. To discourage both types of beetles in the asparagus garden, remove plant debris in the fall to reduce areas where adults can hide and survive. 

Control beetles by encouraging beneficial insects such as the tiny green parasitic wasp and lady beetle larvae and other insects that can reduce the number of feeding beetles. Use of pesticides should be considered carefully since they can damage both helpful and harmful insects. Avoid using pesticides when plants are flowering since they may harm foraging bees. Also check the label when considering pesticide use to ensure the number of days between application and harvest is followed.
 
Cutworm-Cutworms arrive as night-flying adult black and tan moths that produce dark grey to black 2- inch caterpillars. The caterpillars hide in the soil near plants during the day and feed at night.  Eggs are laid in grasses or weeds in May or June, hatch after a few days, then emerge to feed. The larvae are called cutworms because they curl around the plant stem and feed on it, which cuts off the stem at or below the soil surface. The plant may also appear wilted if the stem is only partially chewed through.  Monitor the soil within 12 inches of the damaged plant by sifting through clumps of soil and/or checking nearby hiding places. When disturbed, the cutworms will curl into a “c” shape. Physically remove any larvae and drop them into soapy water. Make the garden environment unattractive for cutworms by removing weeds or plant debris that may harbor larvae, and encourage beneficial predators such as parasitic flies and wasps.  Use aluminum or cardboard collars pushed several inches into the ground and extending above ground around new plantings to prevent larvae from crawling onto the plants.

 
Asparagus aphid- This insect overwinters on asparagus debris left in the field. The eggs are laid by small grey-green adults in the fall and the nymphs that emerge in the spring are capable of reproducing every 10-20 days. Signs of aphid presence include twisted and curled or yellowed leaves, deformed or dead shoots and abnormal plant growth on the lower portion of the fern. Accumulation of honeydew, a sticky secretion produced after aphid feeding, does not harm the plant but can attract other insects that feed on it. Sooty mold is a dark fungus that can grow on the honeydew. While unsightly, it is not harmful to the plant. Control asparagus aphid by removing dead material during fall cleanup and harvesting spears regularly in the spring to minimize their food source prior to fern growth. Spray plants with a strong jet of water to dislodge the aphids, introduce beneficial insects such as lacewings or ladybeetles, or use horticultural oil or insecticidal soap.