what temperature does frost occur
A light frost occurs when the temperature drops to below 32 degrees Fahrenheit, and refers to the conditions that allow a layer of ice crystals to form when water vapor condenses and freezes without first becoming dew. Harvest basil and other tender herbs before a light frost (when the temperature drops to 32 degrees Fahrenheit). 2  Even if they survive the frost, they don't do well in cold temperatures. 3  The same is true for most annuals.