312 The Principles oj Vegetable -Gardening 



be gathered. A very common method is to clear away 

 the vines and then to plow up the potatoes with a " hill 

 sweep" (2 -winged furrowing plow). They are gathered 

 into small piles, where they remain until removed from 



the field. The common 

 method of storing is to 

 bank them in a cone- 

 shaped pile. This pile 

 is then covered with 

 hay, and this is thatched 

 with cornstalks, or cov- 

 ered shingle - like with 



Fig. 88. Vineless sweet potato. 



pine bark. It should 

 be kept dry and should be on a slightly elevated place. 



One bushel of ordinary sweet potatoes will give from 3,000 to 

 5,000 plants, if the sprouts are taken off twice. The plants are 

 usually set in drills, which are 2X~3 feet apart. The plants stand 

 12-18 inches apart in the drill. At 18 x 36 inches. 9,680 plants are 

 required for an acre. These should be produced by 2-3 bushels of 

 "seed" tubers. An average good yield of sweet potatoes is 200- 

 400 bushels per acre. Yields twice as high as these are sometimes 

 secured. 



The sweet potato is one of the Morning-glory and Moon- 

 flower tribe, Ipomoea Batatas. It has been cultivated from very 

 remote times by the aborigines. It is probably native to tropical 

 America, although it is widely distributed in tropical countries. 

 The top is a trailing vine, which roots at the joints and bears 

 variable but mostly halberd -form leaves. Some varieties have 

 longer vines or tops than others, and some have short not- running 

 tops, as the "Vineless Yam," now popular in the South (Fig. 88). 

 The sweet potato blooms only rarely, and even then it may not 

 produce seeds. 



Sweet potatoes are grown very extensively in the United 

 States, and they are shipped to all parts of the country, being one 



