380 FUNDAMENTALS OF FRUIT PRODUCTION 



Orchard heating is not so common as it was some years ago. Certain 

 sections have abandoned it altogether, in others only a few growers 

 continue it. In some instances too much has been expected of it; in 

 others the falling in fruit prices from an artificial level has been a con- 

 tributing cause, but probably in the majority of cases it has been aban- 

 doned for the excellent reason that it has not paid. 



It will be seen from the Wauseon figures that heating at that point 

 would be an expensive insurance considering the number of times it 

 would be useful. If, in addition, the orchards are, as is the case fre- 

 quently, bearing chiefly in alternate years, the likelihood of heating being 

 profitable over a long term is further reduced. Assuming a damaging 

 frost in half the blossoming seasons, a ratio far greater than that for the 

 largest apple growing sections, and assuming a crop in alternate years, 

 the chance of heating being required to save a crop is 3^^ X M or 1 in 

 4. If damaging frost occurs once in 3 years the chance is 3^^ X li or 

 1 in 6. At Wauseon, with very liberal allowance, it is, for the King 

 apple, 2 in 15. It is significant that much of the experimental work on 

 orchard heating has been done at temperatures above freezing because 

 there was not enough frosty weather for all the tests. There are, too, 

 in almost all sections, springs when the crop is damaged by high cold 

 winds, under such conditions that heating fails to protect it sufficiently. 

 If a season of this kind is added to seasons when heating is unnecessary 

 the number of years when it really pays is still further reduced. 



The fruit grower is forced, sooner or later, consciously or uncon- 

 sciously, to consider the economic doctrine of marginal utility. This 

 means, as applied to the topic under discussion, that until all the land 

 otherwise well adapted to fruit growing and free from frost danger in a 

 given area is in use for that purpose it is of doubtful expediency to attempt 

 fruit growing on land that will require heating. It means, too, that in 

 seasons when profits in general run low they are, other things equal, 

 wiped out first on the land that requires heating. 



In addition to the doctrine of marginal utility the grower should 

 apply to his analysis the law of the minimum. Orchard heating is 

 not hkely to be profitable to him if his spraying is defective, his pruning 

 poorly done, his land lacking in drainage or irrigation, his trees weak or 

 if his fruit is not marketed to advantage. "When he is satisfied that he has 

 developed these essentials so that none of them is hmiting his profits and 

 that frost is the limiting factor he can consider orchard heating. In some 

 cases it will be profitable; in more cases it will not. 



FROST EFFECTS 

 Manifestations of frost injury aside from the dropping of the fruit 

 are sometimes found. The so-called bull-necked pears previously men- 

 tioned are rather common and are sometimes confused with seedless 



