ROOT, TUBER, AND BULB CROPS 95 



154. Horse-radish. The root of this plant, ground and 

 placed in vinegar, is used as a relish. Horse-radish is propa- 

 gated by root-cuttings, the smaller branching roots being 

 removed to furnish the cuttings at the time the larger roots 

 are dug for market. Roots one-fourth or one-half inch in 

 diameter are made into cuttings from four to six inches long, 

 the upper end of the cutting being cut squarely across and 

 the lower end slanting in order to indicate which end should 

 be upward in planting. The cuttings are stored over winter 

 in sand kept slightly moist, and are usually planted in the 

 spring. In planting, the cuttings are set with the upper end 

 just beneath the surface of the soil. A good loam, rich in 

 humus, is best for horse-radish (Fig. 66). 



155. Jerusalem artichoke is native to Canada and the 

 northern part of the United States. Like those of the Irish 

 potato, its tubers can be used as a table vegetable and in 

 the making of soups and salads. The plant is a perennial, 

 propagating itself from year to year. It grows well in poor 

 sandy soils, but also responds to good soils. It is propagated 

 by tuber-cuttings. 



156. The parsnip is thought to be a native of Europe. 

 It requires a long growing season, and for that reason the 

 seed is sown in early spring. Parsnip seed produced the 

 previous season should be sown, as older seed does not have 

 power to germinate. Germination of even the best seed is 

 slow. A deep loam is most suitable for the parsnip. The 

 roots do not grow well in the hot summer months, but in- 

 crease in size rapidly during the cooler autumn weather. 

 The roots desired for winter use may be dug in the fall and 

 stored, but as freezing improves rather than injures them, 

 they are commonly left in the ground and are dug early in 

 the spring when the ground has thawed out. The cultural 

 directions for the parsnip are the same as for beets or carrots. 



157. Irish potato. The potato is a native of South Amer- 

 ica. De Candolle states that the Spaniards introduced it 



