It is common to hear growers describe the influence of nutrition management on improving freezing resistance. There are several possible mechanisms that reduce the freezing temperature of the fluid within the cell. We have observed freezing resistance gains of about 6 degrees Fahrenheit.
When sugar content increases, this will have the effect of reducing the freezing temperature, just like when you put too much sugar in the ice cream.
Potassium, chloride, sodium, nitrates, or magnesium are electrolytes, when the levels of these nutrients increase, it reduces the freezing temperature much like salt lowers the freezing temperature of water. Of course, there is a very large downside to having high levels of these nutrients, because a high EC within plant sap also weakens cell membranes. A delicate balance needs to be maintained with these nutrients.
Field experience suggests that elevated levels of trace minerals, particularly manganese and boron, but also zinc, copper, iron and cobalt can reduce freezing temperatures significantly, and within days or hours of application, even when plants are dormant. I don’t have a hypothesis for how this might work, I just know it does. Seaweed applications are also known to have this effect.
Here is a photo of a rye crop in KS earlier this spring. Part of the field received a foliar application of Forage Foliar blend, which includes the trace minerals mentioned and seaweed on April 2nd. There were overnight low temperatures ranging from the low to high 20’s Fahrenheit on April 10, 11, and 12. The foliar application line is clearly visible at a distance, where the untreated plants have a good bit of frost damage, and the foliar treated plants have none. This photo is of the spray line boundary, with treated plants on the lower left.