Interesting reads - frost protection

Here are two links to some interesting articles about frost protection:

The fao link is 7 or so chapters long, you have to use the arrows on the page to advance chapters. It has a lot of technical information:

http://www.fao.org/docrep/008/y7223e/y7223e06.htm#TopOfPage

The next link is more of a novelty read from 100 years ago describing some interesting ways people battled with frost events in the past, including using explosions! :

https://naldc.nal.usda.gov/download/IND43744703/PDF

“Frost” from water can occur at temperatures below 42°F depending on humidity and air pressure, and nearly always below 32°F. Out here in the southwestern U.S. we often see it occuring on grasses when overnight temperatures drop below 37°F. Consequently, advice on frosts and freezes are interpreted differently in our locale.