霜冻警报！大多伦多连续两夜降温 花草受影响！长周末有雨

The Myth of Misting A lot of citrus growers run sprinklers on the ground and over trees when temperatures dip, but it’s important to understand that ice does not protect the tree—protection results from how water releases heat as it freezes and melts, allowing the encased plant tissue to remain around 32 degrees Fahrenheit. It works for trees during the continuous freezing of additional water that is being applied constantly. The most effective watering is through using mist nozzles which put out a finer spray than regular garden sprinklers, using very little water. It is important to start this treatment well before it gets down to freezing, and then continuously until the temperature rises above freezing, or at least until ice in the shade outside the orchard begins to melt. And even then, it helps just when the temperature dips into the upper 20s—not much at all once a really hard freeze sets in. So watering—really, continual misting—is not that practical, and is only good during fairly mild freezes. Back to dragging out strings of light bulbs and coverings.