30 Farmers' Bulletin 1096. 



will flow into the wagon tanks by gravity. Where the ground is not 

 too flat, the storage tank can be so located that the oil can be put 

 into it and taken out by gravity. If more than 5 acres are to be fired 

 with oil a portable tank from which to fill the heaters is almost a 

 necessity on account of the saving in time and labor. Three men 

 with a tank wagon can fill heaters very rapidly, one man driving 

 and two men drawing oil into 5 -gallon buckets and pouring it into 

 the heaters, filling two rows at the same time. The owners of two 

 adjoining orchards often use the same tank wagon. 



Owners of small orchards often handle the oil in metal drums 

 of about 50 gallons capacity. The heaters are filled directly from 

 the drums, which are hauled through the orchard on sleds. 



IS ORCHARD HEATING PROFITABLE? 



This question can be answered only by the individual grower, as 

 the factors to be considered in drawing a conclusion vary greatly, 

 sometimes even for orchards within a few miles of one another. 



The most important points to be considered are as follows : 



1. What has been the average loss from frost damage in your orchard dur- 

 ing -a period of years as long a time as possible? Unless these data are avail- 

 able from personal experience they will usually be difficult, if not impossible, 

 to obtain, although neighboring fruit growers may sometimes be able to supply 

 some information, As a general rule, few records of this kind have been kept. 



2. How many times during this period of years would it have been necessary 

 to light the heaters in order to have saved the entire crop each year? If de- 

 pendable temperature records have been kept for a number of years somewhere 

 in the immediate vicinity and are still being kept at the same location, a com- 

 parison of records from the orchard and from the station with the long record 

 for the same season may make it possible to gain a fairly accurate conception 

 of what temperatures have been experienced at the orchard in question. 



3. Will the value of the fruit lost through frost damage more than pay in- 

 terest and depreciation charges on an investment for all necessary heating 

 equipment, together with all costs of operation? 



4. Is your locality likely to be visited by short periods of extremely cold 

 weather during the growing season that may badly injure or kill the trees? 

 This question can probably be determined from Weather Bureau records from 

 some station in the vicinity. 



There are two conditions under which orchard heating will not be 

 profitable. The orchard may be located where frost damage is too 

 slight in the long run to pay the expenses of heating, or the orchard 

 may be in an exceptionally cold section where damaging frosts occur 

 so often that the costs of protection are too great to be borne by the 

 crops. 



The number of cases of the first-mentioned type is smaller than 

 would appear at first thought. The saving of one season's crop, which 

 would otherwise have been a total loss, will justify the expense of 

 heating for a good many years. Some practical growers consider it 



