276 CULTURE OF IRISH POTATOES 



effect on quality and yield of crop, and expense of planting and 

 digging. 



Deep planted potatoes are considered of best quality, as they are 

 smoother, none are sunburned, and they are more uniform. 



Yield is usually improved with planting 4 to 5 inches below 

 the level surface, rather than shallower. As pointed out heretofore, 

 new tubers arise from underground stems that are produced at the 

 nodes. It is claimed that deep planting, by increasing the number 

 of underground nodes, favors larger yields. This theory, however, 

 'has not been well substantiated. Deep planting is a disadvantage in 

 cold, wet soil, when quick germination and an early crop is desired. 

 For this reason early potatoes should be planted shallow though they 

 may be covered deeper after germination. 



In practice, potatoes are commonly planted shallower than four 

 inches, in some regions only two inches below the level. Where shal- 

 low planting is practised, the soil is ridged up about the plants in 

 cultivating in order to provide plenty of room for the tubers, and 

 prevent sunburn. The principal reason for shallow planting is 

 ease in harvesting, especially where hand digging is practised. 



Hill vs. Drill Planting. Where machines are used, drill plant- 

 ing is the general practice, and, while there is little experimental evi- 

 dence, probably gives better yields, especially where large quantities 

 of fertilizer are used, as the roots have a more uniform distribution 

 in the soil. 



Hand planting is practised where the area grown is small, or 

 where hills are too steep for machines. In some regions, as northern 

 New York, the vines are so heavy that hand-digging is necessary. 

 Where machinery can not be used, hill planting has several advan- 

 tages: (1) easier to plant; (2) takes less seed; (3) easier to culti- 

 vate; (4) easier to dig. 



Level vs. Ridge Cultivation. It is the general custom to 

 throw up a rather high ridge around the potato rows or hills. It is 

 easier to kill weeds by high ridging, and also makes digging much 

 easier. While deeper planting and level culture usually give some- 

 what greater yield, the labor cost is greater and generally believed 

 to offset the prospect of higher yield. The ridging, however, can 



