Frost

Curitiba (Southern Brazil) is the coldest of Brazil's state capitals; the greenhouse of the Botanical Garden of Curitiba protects sensitive plants.

Frost is ice that is formed when water vapor freezes onto a surface. It has a white, powdery appearance. It forms on cold surfaces when the temperature of the air is very low. It can destroy crops. This can cause mass hunger.

Many plants can be damaged or killed by freezing temperatures or frost. This varies with the type of plant and tissue exposed to low temperatures. Greenhouses help to protect crops from cold and frost damage.

Frost Media

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  A patch of grass showing three zones.*

  1. *
  2. crystalline frost in the below-freezing shade (blue, lower right)*
  3. frost in the warming but still below freezing strip most recently exposed to sunlight (white, center)*
  4. frost-free region: here, the previous frost has melted from a more prolonged exposure to sunlight (green, upper left.)
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  Frost in the highest town in Venezuela, Apartaderos: Because of its location in an alpine tundra ecosystem called páramo, a daily freeze-and-thaw cycle, sometimes described as "summer every day and winter every night", exists.

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  A spider web covered in air hoar frost

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  Hoar frost

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  A flower with advection frost on the edges of its petals

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  Dead plant leaves during Winter Storm Uri in a backyard in Northern Mexico, with below freezing temperatures.

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  Frost on the grass of a public park in November

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  Map of average first killing frost in Ohio from "Geography of Ohio," 1923

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  Roses with protection against frost – Volksgarten, Vienna