Frost is the enemy of our sweet little strawberry and blueberry plants, not to mention our infant christmas trees too. If the newly forming flowers and buds were to frost over, we could lose a lot of our fruit for the upcoming harvest-your-own seasons. So, what can we do to help our babies survive? We freeze them.
Farm crew members will stand vigil over the fields all evening to be sure that the sprinkler system continues working properly until the air temperatures reach back into a healthy level for the plants.
The water spraying from the sprinklers falls in a fine mist around the buds and creates a frozen shield around the growing fruit. The freezing keeps the buds warm inside. Wait! Did I just say that freezing keeps them warm? Yes, yes indeed I did. Ready for some science? Ok, here we go.
When you withdraw thermal energy from a liquid or solid, the temperature falls. When you add heat energy the temperature rises. However, at the transition point between solid and liquid (the melting point), extra energy is required (the heat of fusion). To go from liquid to solid, the molecules of a substance must become more ordered. For them to maintain the order of a solid, extra heat must be withdrawn. In the other direction, to create the disorder from the solid crystal to liquid, extra heat must be added.
What does all that mean? As the water becomes a solid heat must be withdrawn. That’s right, heat is needed to make ice. SO, while the buds are freezing the heat of fusion will keep them warm.
Ok, I admit, while spraying yourself with the garden hose on a cold night probably isn’t the best idea to keep yourself warm, it sure is working for our plants. Just ask the Jones farmers who have recently been spending long hours watching the ice keep our berries warm!
So, in a few weeks, while you’re here picking the strawberries, take a minute to think back to these photos (you can click on the photos to see larger versions) and how several icy nights have helped to make your trip a “fruitful” one.