The pandemic, coupled with the cold winter has consumers demanding annuals, herb, and vegetable transplants weeks before the last average frost date. As growers, you obviously want to cash in and take advantage of these impulse purchases. But we all know this is risky! What can you do to prevent losses during those unpredictable cold snaps that occur in April and even into May? In this alert, we will provide some tips on how to protect your crops and provide you with a
list of cold-hardy plants you should be selling.
The above normal and record-breaking temperatures this past March has consumers visiting garden centers in search of anything to plant in their garden. This means that unacclimated plants could be sitting on outdoor garden center benches, on a flatbed trailer or wagon in front of your greenhouse.
When should you be concerned about these crops and what can you do to protect them from injury or death as cold temperatures will inevitably return? What does it mean when the weather forecast say there is a “frost” and “freeze” warning or watch?
What is freezing injury?
Freezing injury is damage that occurs to plant tissues when temperatures are below 32 ºF. Pure water freezes at 32 ºF,
however, water in plant tissue has dissolved salts (ex. plant sap), which freezes at temperatures a few degrees below 32 ºF. If water freezes in a plant cell, the sharp ice crystals can cut cell membranes, resulting in fluids leaking from the cell, leading to cell and plant
death. Freezing injury symptoms include tissue browning, dark green foliage that then appears water-soaked, blackening, wilting, or curling of leaves and stems.
Young plant tissue is more vulnerable to freezing than mature tissue. The cold tolerance of hardy and frost tolerant crops to freezing temperatures increases as the plants are gradually acclimated to cooler temperatures over time. In other words, a cold-hardy plant grown in a warm (heated) greenhouse is more susceptible to freezing
injury in the garden center than one that has been in a cold frame, high tunnel, unheated structure, or outdoors.
Read the complete article at www.e-gro.org.