Why Do Apples Need Chilling Learn About Chill Hours For Apple Trees
Apple Chilling Info So, you’re immersed in choosing bare root apple trees from a catalogue for your particular USDA zone and notice that not only is the hardiness zone listed but another number as well. In the case of apples, these are the number of apple chill hours needed for the tree. Okay, but what the heck are chill hours for apple trees? Chill hours or chill units (CU) are the number of hours when temperatures stay at 32 to 45 degrees F....