408 
VEGETABLE GARDENING 
The soil should be thoroughly prepared before sowing. 
From r /> to I inch of soil is sufficient covering. As the 
seedlings are very small and delicate at first, it is cus- 
tomary to use plenty of new seed, and then thin the 
plants to 6 or 7 inches in strong soils and 4 or 5 in pooler 
ones. There should be 15 to 18 inches between rows for 
wheel-hoe cultivation, and 2 feet or more when horse 
implements are to be used. 
The roots may be used any time after they have 
reached maturity. Most gardeners who grow them in 
large amounts dig part of the crop in the fall, burying 
the roots in the ground or storing them in pits, caves or 
cellars. To prevent drying and shriveling in storage, they 
should be covered with moist sand or soil. As the roots 
are perfectly hardy in all parts of the North, the greater 
part of the crop is usually left in the ground where it 
was grown until suitable weather for digging the follow- 
ing spring. Freezing improves the quality (although this 
idea is sometimes refuted). The roots come out of the 
ground in a bright, fresh condition, and are salable on 
most markets. Parsnips are easily grown, and all mar- 
kets should be well supplied. 
PEA (Pisum sativum) 
553. History. — Decandolle (“Origin of Cultivated 
Plants,” p. 330) makes the following statement in re- 
gard to the origin of the garden pea: “The species 
seems to have existed in western Asia, perhaps from the 
south of the Caucasus to Persia, before it was cultivated. 
The Aryans introduced it into Europe, but it perhaps 
existed in northern India before the arrival of the east- 
ern Aryans. It no longer exists in a wild state, and 
when it occurs in fields, half-wild, it is not said to have 
a modified form so as to approach some other species.” 
554. Importance. — The pea is one of the important 
