HARVESTING THE CROP 



277 



be too high, injuring some roots between rows, and the best growers 

 say that a moderate ridge, 4 to 5 inches, is best. 



Tools for Cultivation. The harrow or weeder is often used 

 first, even before the potatoes are up if weeds appear or the ground 

 is crusted by rains. The use of the harrow and weeder may be con- 

 tinued until the crop is six inches high. This is followed by culti- 

 vators (Fig. 108), usually with narrow blades, to give a fine, even 

 surface. If weeds start in the row, considerable earth is ridged up to 

 cover them. 



FIG. 108. A good type of cultivator. The rows have already been ridged with a hiller. 



One light hoeing is usually necessary to kill all weeds. Cultiva- 

 tion is usually continued until the vines cover the ground. In many 

 places a sweep plow is used the last going over, to ridge up and make 

 sure that no tubers will be exposed to the sun. This practice is most 

 common on shallow, gravelly soils, where the potatoes normally 

 develop very near the surface. In deep loam soils the sweep is 

 seldom used. 



Harvesting the Crop. Special harvesting tools have evolved 

 from the older farm tools (Fig. 109). The spade has developed into 

 the potato fork, the hoe into the potato hook, while in the plow the 

 mould-board has been replaced with iron rods in the simplest form 



