192 The Principles of Fruit-growing. 
ment upon certain hard lands which are much in- 
clined to be dry. 
Oats, wheat, barley, millet, and various other 
quick-growing crops may be utilized as covers, but 
they are less adapted to the purpose than those 
which have been mentioned. In order to impress 
the different qualities of cover crops upon the 
mind, it may be well to say that rye and corn, and 
the like, are to cover crops what pigs and mules 
are to domestic animals. 
Amongst the leguminous crops are the various 
kinds of peas, heans, vetvhes, and the eclovers. If 
it is desired to grow a leguminous crop upon land 
which is hard and dry, it will be necessary to 
choose those with large and quick-germinating seeds, 
like the beans and the field peas. Common field 
beans may be sown broadcast late in the season, 
and if they ean have six weeks of uninterrupted 
growth, will make a good cover before killed by 
frost. Canada peas are not injured Jy the early 
frosts of fall, and therefore may be sown _ later. 
At the Cornell Station, peas sown as late as the 
20th of September reached a height of about six 
inches, and were large enough to afford a fairly good 
cover, if they were sown very thick. But, in gen- 
eral, in the northern states, it is advisable to sow 
not later than the last of August or the first of 
September. 
The cow pea (Vigna NSinensis) can often be used 
to the greatest advantage, especially in the middle 
and southern states, where the long seasons allow 
