448 FIELD CROPS 



they may be 2J^ by 2 feet or even 2^ by 2^ feet. Plants 

 are usually set about 16 or 18 inches apart when planted in 

 ridges. It is not necessary to mark the rows if a transplant- 

 ing machine is used. 



588. Setting the Plants. The plants should not be set 

 in the field till all danger of frost is past. The setting may 

 be done by hand or with a transplanting machine. If the 

 plants are to be set by hand, the work can be hastened by 

 opening a shallow furrow down the line of the ridge or along 

 the mark. The principal things to observe in setting are to 

 have the roots and the soil moist and to press the earth 

 firmly about the plants. Planting as soon as the ground can 

 be worked after a rain or putting a half pint or so of water 

 in each hole will help materially in getting a good stand. 

 Only strong, well-rooted plants should be set. 



589. Cultivation. The cultivation of sweet potatoes is 

 not different from that given to most other cultivated crops. 

 The surface of the soil should be stirred often enough to 

 prevent the growth of weeds and to hold the soil moisture. 

 One or two hoeings may be necessary to remove the weeds 

 from the rows. Shallow cultivation should be given after 

 each rain till the vines have covered the ground pretty com- 

 pletely, when the field should be "laid by" by throwing some 

 earth toward the row at the last cultivation. 



590. Digging. Sweet potatoes should be dug before frost, 

 as they are easily injured. If the vines freeze before they are 

 dug, they should be cut away at once to prevent the frozen 

 sap from going back into the roots. The potatoes are usually 

 plowed out, a rolling coulter being used to cut the vines. 

 Care should be used in harvesting and marketing to avoid 

 injury to the potatoes; the ordinary potato digger is quite 

 likely to bruise them, and a bruised sweet potato does not 

 keep long. The potatoes are usually picked up by hand and 



