WINTER PROTECTION ' 291 



Notwithstanding the claims of so-called "weather sharks," it is 

 impossible to consistently forecast local frost without systematic 

 knowledge of conditions over a wide area. It is far better to rely on 

 the experienced, scientifically worked out predictions of the Weather 

 Bureau reinforced by a knowledge of the conditions that are favorable 

 to frost occurrence. Then when frost warnings are issued one can 

 judge whether or not precautions are essential in his immediate 

 locality. 



Conditions That Suggest Frost 



1. Weather comes in "waves," hence an abnormally warm spell 

 during the frost season is liable to be followed by a sudden drop in 

 temperature. 



2. A clear sky permits increased radiation and improves the 

 chances of frost. 



3. The passing of a storm is usually followed by "clearing and 

 colder," which often means a frost. 



4. A still, clear air with a steadily falling temperature in the late 

 afternoon is a good sign of frost. 



5. Frosts are more hkely to occur in the open country and in 

 small villages than in and near large cities; they occur on lowlands and 

 in "pockets" and valleys sooner than on hillsides; they are less frequent 

 near bodies of water than away from lakes, the ocean, etc.; northern, 

 western, eastern and southern slopes are frosty in decreasing order as 

 given; sandy, well drained, and dark colored soils are less liable to 

 frost than heavy clays and wet, poorly tilled, light colored types. 



To Ward Off Frost 



Since frosts accompany dry, clear, still air and the radiation of 

 heat from the ground and plants, the following methods of preventing 

 them can be employed in the small garden according to the means at 

 hand: (1) Heating of the air by means of smudge fires, orchard 

 heaters, etc.; (2) the moistening of the air by means of sprays; (3) 

 a combination of (1) and (2), such as the discharge of waste steam into 

 the air; (4) ventilation, or the stirring of the atmosphere, to prevent the 

 setthng of layers of cold air on the plants; (5) irrigation by the furrow or 

 flooding system; (6) the covering of tender plants with cloths, paper, a 

 mulch, etc.; (7) the spraying of the plants themselves both to prevent 

 the formation of frost and to help thaw out hardy plants that may have 

 been touched overnight. 



