CHAPTER III 



CLIMATIC REQUIREMENTS 



THE potato grew wild and now grows to per- 

 fection in southwestern Colorado, in the 

 Rocky Mountains, and under similar con- 

 ditions in the Andes Mountains in South America. 



In these districts the winters are cold, and the 

 ground is generally covered with snow from early 

 fall before the ground freezes until late in the 

 spring. There is often a heavy blanket of snow 

 until May. In the growing season there are 100 

 to 110 days between killing frosts. During this 

 period the nights are cool, but there are twelve to 

 fifteen hours of bright, intense sunshine during the 

 day. Occasional light showers of a few minutes' 

 or hours' duration occur, but the total summer 

 rainfall is very small in comparison to the total 

 for the year. 



Nothing but the strongest plants and animals 

 live under these conditions, but such grow to the 

 highest perfection and strength. The air is vital- 

 izing and invigorating. Vigorous, healthy people 

 choose it, while debilitated people of low vitality 

 prefer more mild conditions. 



Long hours of bright sunshine make the potato 

 in its native home free from disease; and where 

 the tuber is grown under less favorable conditions 

 the ingenuity of man has supplied as nearly as pos- 

 sible the things that nature has furnished in the 

 Rocky Mountain region referred to. 



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