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Asparagus (Green)

Recommendations for Maintaining Postharvest Quality

Trevor Suslow

Department of Plant Sciences, University of California, Davis

Maturity & Quality

Maturity Indices

Asparagus spears are harvested as they emerge through the soil from the underground crowns. Typically, spears are cut when they reach approximately 23cm (9 in). Stalk diameter is not a good indicator of proper maturity and associated tenderness. (See Quality Indices)

Quality Indices

Quality, fresh asparagus will be dark green and firm with tightly closed, compact tips. Stalks are straight, tender and glossy in appearance. U.S. grades are No. 1 and No. 2. California grades range from small (0.47 cm/3/16 in) to Jumbo (2.1 cm/ 13/16) but diameter is not a good indicator of tenderness quality. Washington state standards, XF (Extra Fancy), are being adopted that specify tolerances which are somewhat more stringent than U.S. No. 1.

Temperature & Controlled Atmosphere

Optimum Temperature

0°C-2°C (32°F-35.6°F)

Storage life is typically 14-21 days at 2°C and can be extended up to 31 days by 7-10 days storage at 0°C and atmospheric modification. Extended storage (~10-12 days) in air at 0°C may cause chilling injury.

Optimum Relative Humidity


High relative humidity is essential to prevent dessication and loss of glossiness. Drying of the butt-end of spears is a negative quality factor. Commonly asparagus is packed and shipped in cartons with a water-saturated pad to maintain high humidity.

Rates of Respiration

°C (°F)
ml CO2/kg·hr
0 (32) 14-40
5 (41) 28-68
10 (50) 45-152
15 (59) 80-168
20 (68 138-250
25 (77) 250-300

To calculate heat production multiply ml CO2/kg·hr by 440 to get Btu/ton/day or by 122 to get kcal/metric ton/day.

Rates of Ethylene Production

Responses to Ethylene

Exposure to ethylene will accelerate the lignification (toughening) of asparagus spears in controlled studies. The concentration and duration of exposure to exogenous ethylene, to cause this effect, at commonly encountered levels during storage and distribution are not available.

Responses to Controlled Atmospheres (CA)

Elevated CO2 at 5-10% (typically 7%) in air is beneficial in preventing decay and reducing the rate of toughening of the spears. The beneficial effect is most pronounced if temperatures cannot be maintained below 5°C (41°F). Short (CA) exposure to higher CO2 concentrations (12-20%) is safe and beneficial only if temperatures can be maintained at 0°C-1°C (32°F-33.8°F).

Signs of CO2 injury are small to elongated pits, generally first observed just below the tips. Severe injury results in ribbiness.


Physiological and Physical Disorders

  • Asparagus will continue to develop after harvest which is why low temperature postharvest management is critical. Common disorders include upward bending of tips away from gravity and "feathering" (expansion and opening) of tips. Bending will also occur if tips expand to the top of the packaging and are deflected
  • Spear toughening occurs rapidly at temperatures above 10°C (50°F)
  • Bruising and tip-breakage are signs of rough handling and can result in toughening of the spears from wound ethylene
  • Asparagus is sensitive to chilling injury after 10 days at 0°C (32°F). Symptoms of chilling injury include loss of sheen or glossiness and graying of the tips. A limp, wilted appearance may be observed. Severe chilling injury may result in darkening near tips in spots or streaks
  • Freezing injury (water-soaked appearance leading to extreme softening) will likely result at temperatures of -0.6°C (30.9°F) or lower

Pathological Disorders

The most prominent postharvest disease concern is bacterial soft rot, induced by Erwinia carotovora subsp. carotovora. Decay may initiate at the tips or the butt end. Spears that are re-cut above the white portion of the butt end are reported to be most susceptible to bacterial decay.

Special Considerations

Rapid hydrocooling soon after harvest is strongly recommended. Pyramid-shaped wooden or waxed corrugated boxes for hydrocooling combined with center-loading during shipment promote good cooling-air circulation.

Disorders Photos

Title: Asparagus Bending

Photo Credit: Leonard Morris, UC Davis 

Title: Asparagus Flower Initiation

Photo Credit: CDFA 

Title: Bacterial Soft Rot on Asparagus Tips

Photo Credit:  Cantwell, Marita Department of Plant Sciences

Title: Broken Tips

Photo Credit: CDFA 

Title: Crooked Spears

Photo Credit: CDFA 

Title: Frozen and Thawed Asparagus

Photo Credit: CDFA 

Title: Split Spears

Photo Credit: CDFA 

Title: Wilting

Photo Credit: CDFA 


August 1996

Use of Materials

The UC Postharvest Technology Center grants users permission to download textual pages (including PDF files) from this World Wide Web site for personal use or to reproduce them for educational purposes, but credit lines and copyright notices within the pages must not be removed or modified.

Except for these specified uses, no part of the textual materials available on the UC Postharvest Technology Center Web site may be copied, downloaded, stored in a retrieval system, further transmitted or otherwise reproduced, stored, disseminated, transferred or used, in any form or by any means, except as permitted herein or with the University of California's prior written agreement. Request permission from UC Postharvest Technology Center. Distribution for commercial purposes is prohibited.

The information in this fact sheet represents our best understanding of the current state of knowledge at the time of the latest update, and does not represent an exhaustive review of all research results. Links to any of these UC Postharvest Technology Center pages are permitted, but no endorsement of the linking site or products mentioned in the linking page is intended or implied by such a link.

How to Cite

Author(s) names. Initial publication or update date (located at the top). Title. Link to the specific Produce Fact Sheet webpage (Accessed date)

Example: Cantwell, M. and T. Suslow. 2002. Lettuce, Crisphead: Recommendations for Maintaining Postharvest Quality. (Accessed January 18, 2014).

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