Orchard Heating 



By 

 FRANK L. WEST and N. E. EDLEFSEN* 



INTRODUCTION 



In the state of Utah scarcely a year passes without some 

 damage being done to farm crops, either in the spring or the 

 fall, because of the occurrence of killing frosts. For example, 

 in the spring of 1916 the tops of the young beets ware frozen, 

 about one-fourth of the grain of the northern part oi the state 

 was frozen, the yield of the first crop of alfalfa was about half 

 normal and 90 per cent of the fruit of the state was destroyed. 

 During the month when fruit buds are in bloom, the report of 

 the U. S. Weather Bureau shows that on an average covering 

 ten years for the five leading horticultural counties, freezing 

 temperatures of 30 degrees, or below, are experienced six nights 

 a year. The county agricultural agents report that three years 

 out of ten the fruit crop is somewhat below normal due to frost, 

 that the crop is considerably below normal one year out of ten 

 for the counties, and that certain orchards in the counties fre- 

 quently lose their entire crop- 



The states of California, Oregon, Colorado, Washington, 

 Ohio, and even as far south as Florida have been heating their 

 orchards on quite a large scale, especially the first two states. 

 Heating on a small scale is being done in parts of more than a 

 dozen other states, (a). 



It is the purpose of this bulletin to report the results of our 

 experiments on orchard heating, to answer the question as to 

 the conditions under which artificial heating would be financial- 

 ly profitable, and to give the most approved method of carrying 

 out the work. 



DELAY OF TIME OF FLOWERING 



The later the buds bloom in the spring, the less chance of 

 their being frozen, because as the spring advances, the tempera- 



*The authors wish to acknowledge their indebtedness to Dr. L. D. 

 Batchelor (now of the University of Calif ornia), and W. H. Homer, for 

 valuable suggestions; Mr. Prank Gates for assistance 'in making the 

 electric heaters; and Mr. J. Z. Richardson and Mr. W. E. Goodspeed for 

 help in making the observations. 



(a) . Monthly Weather Review, October, 1914, No. 42, pp. 562-592. 



