Black frosts are an atmospheric phenomenon that occurs when temperatures drop below 0 degrees Celsius, but without the formation of visible frost on surfaces due to the low humidity in the air.
During the winter season, black frosts mainly occur on clear and windless nights, conditions that favor rapid heat loss through radiation, cooling surfaces to the freezing point.
The phenomenon is known for its devastating impact on agriculture, as affected plants acquire a characteristic dark color due to the freezing of their sap. But how are these frosts classified and how do they impact? We’ll tell you.
Frosts can be classified into different types according to the atmospheric conditions that generate them:
White frosts: They form when there is enough moisture in the air, allowing water vapor to condense and form a visible layer of frost on surfaces.
Black frosts: They occur when the air has very little water vapor and the dew point temperature is below 0 degrees Celsius. The absence of visible frost is due to low condensation, but plants and crops suffer internal damage that manifests the following day with a black coloration.
The damage caused by black frosts is considerable. By freezing the sap inside plants, essential biological processes are interrupted, causing the death of plant tissues.
This type of frost can destroy entire crops in a single night, severely affecting farmers and local economies.
## Recommendations against black frost
– **Protect the roots of plants** with a layer of leaves to prevent cold from penetrating the subsoil, preventing water in the pores from freezing. This is especially useful for trees and plants that are not in vegetative rest.
– **Install an irrigation system** that sprays water on plants when the temperature drops below 1ºC. When freezing, the water releases latent heat (80 calories/gram), protecting plants from extremely low temperatures and keeping tissues at 0ºC.
– **Avoid plowing the soil too much in winter** to allow the hard crust that forms on the surface to act as an insulator against the cold.
– Place fans to move the air and prevent a drastic drop in temperature, especially in radiation frosts where cold accumulates near the ground.
– **Stay informed about meteorological alerts** issued by the National Meteorological Service (SMN) to be prepared for extreme cold conditions.
– Install **systems that provide heat to plants** during the night, such as burners of various fuels.
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