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Asparagus Growing Problem Troubleshooting

Asparagus in rows
Asparagus problems solved
Asparagus is a perennial vegetable that will keep on producing 20 years or longer given the right location and care.

Asparagus is a perennial vegetable that will keep on producing 20 years or longer given the right location and care.

A healthy asparagus patch requires a bit of attention. Rule Number One: Keep ahead of asparagus problems, pests and diseases.

Here is a troubleshooting list of possible asparagus problems with control and cure suggestions:

Asparagus Growing Problems and Solutions:

• Yellow to orange to reddish brown or black pustules on stems and leaves. Asparagus rust is a fungus disease. It is most prevalent in humid regions. Spear tops turn yellow and brown and die back. Plant resistant varieties such as Mary Washington and Martha Washington. Cut down diseased fern at the crown and destroy them.

• Plants and leaves are yellow. Overwateing and poor drainage. Allow soil to dry to a depth of 4 inches before watering again. Check soil pH; add lime if the pH is below 6.5.

• Plants are weak and spindly; few spears. Harvest was too early or too heavy. Plants must be allowed to store food for the next season before they go dormant. Asparagus should be picked the first year it is planted; the second year harvest for two weeks and the next year for 4 weeks. Stop harvesting when spears are thinner than a pencil.

• Spears are crooked, curved or malformed. Wind can distort spear growth; protect asparagus from prevailing winds. Too close cultivation will cause spears to malform: plant at the recommended distance and be careful when weeding.

• Spears are brown or discolored and soft. Frost injury occurs when the crop comes up too early in spring. Discard early spears. Protect crop with floating row covers.

• Spears weaken, wilt, yellow, turn brown, and die. Roots have reddish streaks. This can be caused by (1) Fusarium wilt, a soilborne fungus. Destroy infected plants. Solarize the soil. Rotate plantings; or (2) root rot fungi: rotate crops; plant resistant varieties such as Mary Washington; plant in well-drained area.

• Soft spots on tips and shoots; spear bend and turn white or light green. Phytopthora crown and spear rot is common in wet seasons. Dig out and destroy infested plants.

• Leaves are chewed and slimed. Snails and slugs eat leaves. Collect these pests at night. Set beer traps at soil level to attract and drown snails and slugs.

• Shoot tips are gnawed or channeled. Black stains on shoots. Asparagus beetle is a blue-black beetle; the larva is a dark green-gray grub to about ⅛-inch (9mm) long. Remove infected shoots. Wash away eggs, beetles and larvae with water. Keep the garden free of debris. Use rotenone.

• Shoots are white or yellow stippled. Spider mites suck plant juices causing stippling. Spray with water or use insecticidal soap or rotenone.

• Shoots are eaten near the soil surface. Cutworms are gray grubs in the soil beneath plants. Use cardboard collars around the stem of plants, pushed 1 inch into soil. Uncover and handpick grubs.

Asparagus Growing Success Tips:

Here are essentials to asparagus growing success:

Site and Soil. Plant asparagus in well-drained soil with a neutral pH. Choose a site in full sun and sheltered from the wind. Be rid of all weeds then loosen the soil to 12 inches deep. Add 1-inch of aged compost across the bed and 1 pound of bonemeal per 20 square feet.

Planting. Plant healthy, disease-resistant crowns, but before you do soak the crowns in compost tea for 20 minutes. This soaking will ensure that the crowns make good contact with their new home from the get go. Choose a variety that is resistant to asparagus rust and Fusarium wilt. Male plants will yield better than berry producing female plants. Plant in spring in 6-inch deep furrows setting crown 18 t0 24 inches apart. As the crowns grow fill in the furrow. You’ll be growing stronger plants.

Harvest. Don’t rush your first harvest. Don’t cut spears the year you plant them. The next year, harvest for 2 weeks when spears are pencil thick. The next year harvest for 4 weeks. The next year harvest for 8 weeks. Don’t cut spears thinner than a pencil. For a longer than normal harvest: cut spears for just two weeks in spring then allow 2 or 3 spears from a few of the crowns to mature and produce ferns. These plants will slow in their production for a few weeks while the stalks energize the plant through photosynthesis, then the plants will be ready for 10 more weeks of harvest.

Care. Keep asparagus beds well weeded; asparagus suffers from weed competition. Hand weed or use pruners to cut away persistent perennial weeds. Don’t allow weeds to shadow your asparagus. Always keep asparagus evenly watered. Cover the asparagus in winter with straw or compost mulch. Remove the protective mulch in early spring to allow spears to grow.

More tips: How to Grow Asparagus.

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.


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    • Allow the soil to dry out. If the soil is mulched, move the mulch away from the plants to allow for greater evaporation. If the soil is rich in organic matter, the moisture may move below the roots; if the soil is heavy with clay the roots may rot. Leaves are always the first indicator of distress. Falling leaves does not necessarily mean the roots are damaged beyond survival. Plants want to survive, so time will tell.

  1. I have a new asparagus bed. I have some plants that grew up. We followed it to the bottom and it’s connected to the roots of the asparagus . It doesn’t look like an asparagus. Is it a weed taking nutrients or is it part of the plant

    • Asparagus spears that are not harvested grow tall and have ferny tops. The ferny tops can grow to 4 feet tall or more. They help the roots store energy for the production of new spears next season.

  2. My asparagus bed got trampled when I had construction done on the house (couldn’t be avoided). The plants were bent over but not dug up. Will they be ok next year or they dead?

  3. I have a small bed of asparagus that gets tons of ladybug activity in the summer each year. I have double and triple checked and they are ladybugs, not asparagus beetles. Is it a problem to have this abundance of ladybugs every year? I don’t want to have something harm the plants but if they are beneficial I would leave them be.

    • Purple-skinned or pigmented asparagus is often a reaction to cool or cold temperatures. As temperatures warm, the purple pigment will revert to green.

  4. I planted asparagus in containers on my deck in spring of 2020 and they seem to be doing pretty good. But, a couple of stalks seem a little yellow at the bottom near the dirt. Is this normal? Also, is it okay to harvest them now? If so, where do you cut them?


    • Use a knife or snap the spears just below the soil line; harvest spears that are as big around as your index finger–let the others grow on to become ferny tops to store energy for next season’s spears. The yellowing could be either the lack of moisture or too much moisture in the soil. Feed your plants with a dilute solution of fish emulsion to keep them green.

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