THE SWEET POTATO 445 



583. Varieties. The varieties that are commonly grown 

 in the more northern states are of the Jersey type, including 

 the Big Stem, Yellow, and Red Jersey varieties. The pota- 

 toes are rather short and thick, with light yellow flesh, which 

 is likely to be rather dry, especially late in the season. In 

 the South, the "yam" type of sweet potato is the more popu- 

 lar. The varieties of this type are much sweeter and moister 

 than those of the Jersey type; the flesh may be light yellow, 

 orange, or mottled. The individual roots are usually short 

 and thick, though they may be very slender in some varie- 

 ties. The most popular varieties of the yam type are South- 

 ern Queen, Georgia, and Red Bermuda. 



584. Importance. The area annually devoted to sweet 

 potatoes in the United States is about 640,000 acres. The 

 production in 1909 was 59,222,000 bushels. As the crop re- 

 quires at least four and one-half months without frost for its 

 growth, with plenty of warm weather both day and night, 

 its culture is confined largely to the Southern states, though 

 it may be grown for home use as far north as southern New 

 York and from there westward to Iowa and Nebraska. 

 Sweet potatoes may be grown for market in the South Atlan- 

 tic and Gulf states, the Mississippi and Ohio valleys as far 

 up as southern Iowa and the vicinity of Louisville, Kentucky, 

 and in the central valleys of California. Among the princi- 

 pal districts where the crop is grown on a large scale for 

 market are New Jersey, eastern Maryland and Virginia, and 

 near Merced, California. 



585. Soils and Fertilizers. The best soil for sweet pota- 

 toes is a sand or sandy loam with a clay or clay loam subsoil. 

 The loose surface soil gives the roots a chance to develop, 

 while the heavy subsoil retains the moisture and prevents 

 the formation of long slender roots which are not marketable. 

 Soils of this nature tend to produce the rather short, spindle- 



