74 APPLE GROWING IN CALIFORNIA. 



cheap and coal is so high, it does not seem as though any one would be 

 justified in purchasing coal heaters. It would not be wise to recommend 

 any particular make of heater in this book. In general, the reservoir 

 type of oil heater is the most satisfactory. One can scarcely afford 

 to purchase heaters and other equipment for the work and then fail 

 because of an insufficient supply of oil. Of course, it is possible to 

 refill small heaters, or to have a reserve supply of them on hand, but 

 such entails extra work and expense at time of heating when it is often 

 hard to get enough help. 



PLACEMENT OF HEATERS IN ORCHARD. 



One heater for each tree is ordinarily used. These heaters are 

 commonly placed in the center of the rectangle formed by four trees. 



WHEN TO LIGHT. 



Firing should begin before the temperature has reached the danger 

 point, the object being to keep it at a certain point rather than to let 

 it drop below and then try to raise it again. For example, it is much 

 easier to maintain a temperature of thirty-two degrees when the outside 

 temperature is twenty-five degrees than it is to raise it to thirty-two 

 degrees, after it has dropped down to twenty-five degrees. While fruit 

 buds or blossoms may stand this temperature for a short time, it is never 

 safe to let it get so cold. 



KEEP FIRING WELL AFTER SUNRISE. 



Many a crop of fruit has been lost because fuel played out, or because 

 men became tired or careless and let fires go down at daybreak. The 

 coldest period is very often about sunrise and the heaviest firing is neces- 

 sary at this time. 



USE ONLY TESTED THERMOMETERS. 



To depend upon a twenty-five cent thermometer in the orchard heat- 

 ing business, when thousands of dollars are at stake, is inexcusable fool- 

 ishness, and yet such has often been done. Nothing but reliable, tested 

 thermometers should be used in this important work. Several should be 

 used and placed in different parts of the orchard, as there may be quite 

 a temperature variation in a short distance. Electric alarms may be 

 used, but it is more satisfactory in actual practice to have reliable men 

 to watch the thermometers and record temperatures every few minutes 

 during the time of expected freeze. 



SUCCESS MEANS HARD WORK. 



Our present knowledge of frost fighting with orchard heaters is not 

 such that it can be recommended under all conditions. With the tem- 

 peratures that we usually have during the period of spring freezes in 

 California, it is safe to say that the man who is willing to observe all 

 the details, and who is not afraid of the hardest kind of work, will suc- 

 ceed. Not every man who has orchard heaters does, neither does every 

 man who sprays make a success of that operation. Orchard heating, if 

 ills done at all, should be done rightly, or else all labor and expense may 

 be thrown away. No one who is looking only for the easy jobs should 

 have anything to do with this work. 



