324 CALIFORNIA VEGETABLES. 



not great. As a rule, however, the crop in the upper half 

 of the State is grown in the interior valleys, while at the 

 south, both the coast slopes and the interior valleys yield 

 a fine product. Where the soil is rich, warm, and free and 

 the moisture sufficient, the sweet potato attains immense 

 size and rightly ranks among the great things of Cali- 

 fornia. 



The sweet potato is a strictly tender plant and a heat- 

 lover as well, consequently there is no winter planting, 

 though in drier parts of the State, free from frost, there 

 may be fall plantings which carry their crop well into the 

 winter and for more than half the year fresh potatoes may 

 be taken from the ground, and by proper storing the vege- 

 table may be enjoyed throughout the year. 



Preparation of the Ground. Planting is done at the be- 

 ginning of the frost-free period and the date depends upon 

 the locality. Usually it comes about the first of May, but 

 preparation of the ground should begin earlier to secure 

 good culture and moisture retention as described for other 

 root crops. In regions of good rainfall moisture enough 

 can thus be retained to make the crop, or at least start it 

 well. On dry plains it may be necessary to thoroughly 

 irrigate in the spring before the deep plowing with which 

 the planting is to be made. On loose, lowland soils or in 

 irrigated regions there is often abundant moisture within 

 reach of the plant to serve its purposes and then sweet 

 potatoes may follow a hay or grain crop just as in the 

 practice with common potatoes. Lands which receive 

 moisture from below, and yet are not wet and cold, pro- 

 duce the crop with least labor and expense, though it is 

 quite feasible to proceed with direct irrigation both for 

 planting and after growth. The sweet potato sends its 

 roots to great distances to find moisture. 



Growing the Plants. The sweet potato grows readily 

 by cuttings from the growing vine planted out directly in 

 the field if the ground is moist and warm. This method is 

 followed to rapidly multiply a rare variety. The usual 

 method is to plant the crop by using sprouts from potatoes 



