FROST DAMAGE TO ORCHARDS 



About every mile further south makes as much difference 

 in the season temperature as about eight feet of elevation. That 

 is, a point a mile south of you will have to be eight feet higher 

 than your position to have exactly the same conditions; a 

 point a hundred miles south will have to be eight hundred feet 

 higher. The rule is that every degree of latitude equals five 

 hundred feet of elevation. 



Frost causes an immense amount of damage when not 

 guarded against, however, by freezing blossoms, by freezing 

 fruit before it is fully colored in the fall, by freezing buds, and 

 by stunting and killing trees. A great deal of this damage is 

 preventable by taking advantage of certain natural agencies, 

 or by artificial means. It is not necessary to lose every second 

 or third crop from frost. Even tender fruits, like peaches, can 

 be made to yield every year by applying modern knowledge 

 of preventing frost damage. The degree of cold which hurts 

 fruit at various stages of growth has been learned pretty defi- 

 nitely. It is not always 32 degrees, the water-freezing point. 



Of course, some kinds of fruit trees, buds and blossoms are 

 damaged more easily than others. Dormant peach buds will 

 stand ten or fifteen degrees below zero, some varieties more, 

 others less. When peach buds have swollen the least bit, zero 

 usually will kill them; when showing pink they can stand 

 fifteen degrees above zero; when newly opened twenty-six 

 degrees is the limit. When petals are falling, twenty-eight 

 degrees will damage them slightly, and when petals are off they 

 cannot stand much below thirty degrees. After that, thirty- 

 two is the danger point. 



Apple twigs, and buds, if ripened right, will stand almost 

 any cold. Sixty below zero has been known to kill some vari- 

 eties, but little fear need be felt for any apple tree when 

 it goes into winter in right shape. We have explained this sub- 

 ject in the chapter on cultivation. Apple blossoms showing 

 pink will stand twenty degrees above; full open, twenty-six 

 degrees; with falling petals, twenty-eight or thirty degrees. 

 Pears are about the same as apples. Cherries and plums are 

 slightly more tender; they might need two degrees more warmth, 

 but sometimes their blossoms come through black frosts 

 with no apparent harm. Grape buds seldom will stand tem- 

 perature colder than thirty-one degrees. 



A point to remember is that blossoms may not show any 

 frosting, yet still may be damaged enough to prevent their 

 setting perfect fruit. Gnarly, crooked, small and bitter fruit 

 is not always the result of insufficient pollination or damage 

 by insects or fungi. It may have been caused by frosts in spring 

 or winter. 



The chief means we can make use of to prevent any and 

 all of this frost damage are these: Locate within a few miles of 

 a considerable body of water; locate on a slope, a bench or a 

 hill-top from which air can drain away into lower land; avoid 

 table-lands, plains, and, above all, pockets or valley floors; 

 choose land facing the north or east rather than that facing 

 south or west; cultivate so that trees will be late in starting to 



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