Asparagus Troubleshooting

Asparagus Troubleshooting - Solution Guide

Asparagus Crowns Not Growing

Several factors can exist that cause slow to no spear emergence.

  1. Not growing can mean new crowns were planted too deep or covered too deeply with soil.
    Solution: Plant correctly initially. Once planted, cover with only 2-4 inches of soil over top of crowns. Once new thin spears appear, additional soil can be added carefully with every few inches of new vertical growth until the trench is virtually full.
  2. Not growing can mean crowns are too dry with insufficient moisture for roots to grow.
    Solution: Water. Utilize the 1 inch per week rule, as with other garden plants. Rain events are insufficient or consistent enough to adequately supply new asparagus roots with the water they need to grow.
  3. Little to no growth can mean the soil is too heavy.
    Solution: Properly amend the soil before planting. Heavy clay soils should be well-amended with peat or leaf compost to achieve a healthy 50/50 blend. Soil adjustments after plants are in are virtually impossible. Starting over next spring is the best recommendation.
  4. No growth can mean the crowns were planted upside down.
    Solution: Plant the crowns right side up. Once the crowns are unbundled with the roots spread out on a flat surface, they will look a bit like an octopus, and the old stem stubble should be noticeable on the top of the crown. If you are unsure about which way up, call our customer service team for help.
  5. Not growing can mean it is too soon or too early for new growth to appear.
    Solution: Be patient. Asparagus is a long-lived perennial plant, but it is slow to start growing and emerge from newly planted crowns. It can take up to two months even in optimal conditions for sign of spears to appear. Once spears start growing, cover them with additional soil as they grow to fill the trench they were planted in. (See planting instructions)

Spindly Spears

Spindly, thin spears can result from several things.

  1. Not allowing ferns to grow and fully mature.
    Solution: Let ferns grow to full size. Remove only after frost browns them out at the end of the season.
  2. Roots not established well enough yet.
    Solution: Proper planting. Give plants time to grow and mature. (See above)
  3. Lack of proper nutrition.
    Solution: Proper pH, soil composition, and fertilization is critical for optimal performance. Soil pH is 6.5-7.5 for asparagus. Loose, well-drained, organically rich soil is preferred. Before planting broadcast complete 3-5-3 or 10-10-10 fertilizer at rate of 3-5 lbs. per 100 sq. ft. Top-dress asparagus bed with 2-3 inches of compost or aged manure twice per season, once in spring, and again after harvest in mid-summer.
  4. Competition from weeds.
    Solution: Remove perennial weeds during proper planting. Regularly weed the bed. Limit broadleaf & grass weeds by early season hand cultivation.
  5. Over-harvesting.
    Solution: Do not harvest the first or even the second season. Spears should be minimum of ¼ to ½ inch thickness to harvest. First harvest should only last two weeks, as patch matures longer harvests will be possible. If too many spears are harvested and little to no spears are allowed to grow into ferns, plants will stop producing. (See #1 above)

Spears or Ferns Appear Discolored

  1. Several factors, such as pests, disease, and cultural conditions, can cause discolored spears. Brown soft tips usually indicate frost damage.
    Solution: Prevent frost damage by covering newly emerging spears with mulch or frost cloth. Once damage occurs, there is no cure. Do not harvest heavily damaged crops, instead allow spears to grow into ferns and maintain healthy crop for next year.
  2. Orange, yellow, or gold-colored blistered linear spots developing on fern stems indicate rust disease.
    Solution: Plant resistant varieties like 'Mary Washington', 'Jersey Knight', 'Jersey Supreme', or 'Millennium'. Cut and destroy rust-infested ferns as soon as they are discovered. Rotate new plantings away from the existing infected patch. Never purposefully get ferns wet by spraying with water and allow ferns that do get wet to dry thoroughly.
  3. Yellow, wilted spear tips, or yellowing wilted ferns can be sign of Fusarium wilt infection.
    Solution: Call the County Ag extension office for suggestions. Rotate bed location and plant new crowns. Plant resistant varieties.
  4. Black stained to stippled spear tips can be due to asparagus beetle feeding.
    Solution: Prevent by using floating row covers or adequately timed applications of insecticides with active ingredients, such as Spinosad or Bonide® Pyrethrin, as spears are emerging. The larvae of beetles feed on ferns later in the season.
  5. Pale yellow to white-tipped spears usually indicate spider mite feeding.
    Solution: Scout for more evidence of spider mites themselves or tell-tale webbing and treat with Safer® Insecticidal soap as directed until mites are subdued.
  6. White-colored spears usually lack chlorophyll.
    Solution: Specialty product achieved by preventing sunlight to developing spears. Done by carefully mounding or hilling soil over the spears as they grow.

Malformed or Deformed Spears

  1. Chewed or gnawed spear tips are usually due to asparagus beetles.
    Solution: (See #3 above)
  2. Twisted, narrow, bent, or purple desiccated spear tips with associated linear scoring can be an indication of herbicide damage from 2,4 D or glyphosate (Round-up®)
    Solution: Hand cultivate weeds continually to ensure they do not get out of control and mulch, mulch, mulch. If herbicides are used, ensure the product is labeled for use with asparagus. Safe herbicide treatment is done before planting or in early spring before spear emergence. Organic pre-emergence herbicides can be applied after harvest to prevent late-season weed seed germination.
  3. Bent over, soft yellow spears can be due to crown rot or phytophthora infection.
    Solution: Ensure proper soil drainage and conditions before planting. Limit excess moisture and overly wet conditions. Roots from the base of crown will appear damaged, rotten, and weak typically with linear splits or discolored lesions. Plants with symptoms should be dug and removed. Replant new crowns the following season in a different location.
  4. Windy conditions can cause general curling, crooked, or malformed spears.
    Solution: Planting site should be out of line of strong winds. Once planted in a windy spot, plant or install a protective hedge or windbreak.