News and Stories

FROM THE FIELDS: Heat-Related Quality Issues in Lettuce Items

February 23, 2016

Markon First Crop (MFC) Premium Green Leaf, Iceberg, and Romaine Lettuce packs are limited; Markon Best Available is being substituted as needed.


The Arizona/California desert growing region is entering its third consecutive week of unseasonably warm temperatures that have ranged from the mid-80s to low 90s. The combination of sustained heat and several days of strong winds have caused various quality issues in lettuce and other row crop items over the last several days. Some of the heat-related defects that Markon inspectors have been observing include:

  • Decay
  • Dehydration
  • Dense texture
  • Growth cracks
  • Insect pressure
  • Internal burn
  • Mildew pressure
  • Protruding ribs
  • Rib blight
  • Sun scalding/sunburn

Some value-added lettuce and tender leaf crops are also experiencing several of the above-mentioned quality concerns and will likely exhibit shortened shelf-life from heat stress. Harvesting and processing crews are heavily trimming product in order to better detect and avoid serious defects, but will not be able to eliminate all issues completely. Cooler weather is forecast for the next two days before high temperatures return later in the week. Hot weather will likely continue through the end of the desert season, which ends in late March/early April.


Ordering for quick turns is recommended; maintaining the cold chain throughout distribution is critical to maximizing the quality and shelf-life of commodity and value-added produce items.


Please contact your Markon customer service representative for more information.


John Galvez

Quality Assurance