Cold air is more dense than warm air and will therefore, naturally drain to the lowest point. All parts of the cranberry plant can be killed by cold temperatures, however, the temperature at which they are killed can vary based on their stage of development, prior fertilizer or irrigation regime, temperatures prior to the frost event and other environmental factors. Cranberry flower buds are highly susceptible to frost injury. Since these flower buds are set the year prior to harvest, it is a challenge to keep these buds free from frost injury through the Fall, Winter and Spring. These floral buds are especially susceptible to freeze injury in the Fall as they go into Winter dormancy and in the Spring as they come out of dormancy.
Plants can develop the ability to withstand cold temperatures.
Symptoms and Mechanisms of Freezing Damage Symptoms of freezing injury may appear as water soaking, tissue discoloration or noticeable tissue death. Following a frost event, the terminal bud may appear healthy but a cross section will exhibit a brown center as early as 24 hours following the injury. As ice crystals form between cells, the water inside the cells is drawn out of the cells causing the cell to collapse and loose function. Consequently plants subjected to a bright morning of direct sunlight after a heavy freeze will show freeze damage. Plant Mechanisms of Frost Resistance Plants have several mechanisms by which they tolerate freezing temperatures.