what temp is frost for plants

The temperature at which frost occurs and damages plants depends on the duration of the frost and the type of plant. A light frost occurs when the temperature is between 29°F to 32°F (-2°C to 0°C) and may cause damage to tender plants but little destructive effect on other vegetation. A moderate freeze occurs when the temperature is between 25°F to 28°F (-4°C to -2°C) and can cause wide destruction on most vegetation with heavy damage to fruit blossoms and tender semi-hardy plants. A severe freeze occurs when the temperature drops below 24°F (-4°C) and can cause heavy damage to most plants. It is important to note that the length of time that temperatures are at or below freezing also damages plants, and cold temperatures that last several hours are much harder on plants than an hour or less of freezing temperatures.