By Bonnie Isaac
It’s cold outside! There is snow on the ground. How could this possibly be good for plants?
Many of our fruit and nut trees require a cold period to produce fruit. Without cold this winter, we won’t have fruit this fall. If our fruit trees don’t get enough cold, then the flower buds may not open in the spring. If the flower buds don’t open, they can’t get pollinated. If pollination doesn’t occur, then fruit doesn’t set. It’s an important cycle that is necessary for our food supply, especially if you like fruits and nuts. Apples, pears, plums, peaches, cherries, almonds, and walnuts all require varying amounts of chill time to set fruit.
Chill hours are the minimum amount of cold a tree needs before it will break dormancy. These trees then need a warm period to follow the chill. If it gets warm too soon or the chill requirement is met early, plants may break dormancy too soon, adding risk of a freeze or frost damage. The amount of fruit a tree sets will be affected if there is a late frost or an early warm spell. There is a delicate balance in nature which determines whether we get fruit or not. So, let’s not grumble about the cold outside. Enjoy it! I, for one, really like fruits and nuts. I’ll be nestling all snug in my bed with visions of plums dancing in my head because I know the cold is necessary if I want to enjoy fruit this summer and fall.
Bonnie Isaac is the Collection Manager in the Section of Botany. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.
