106 THE BEGINNER'S GARDEN BOOK 



the plant to get nitrogen, not from the soil, but from the air, 

 so that legumes leave nitrogen in soils where previously there 

 was none. The legumes, then (the clovers, the vetches, 

 alfalfa, peas, beans), are the best plants for green manuring. 

 But most other plants will do. 



The second method of returning humus to the soil is to 

 dig into it the useless parts of all plants that grow in it. The 

 roots usually remain, but the tops of potatoes, com, peas, 

 and beans, the unused leaves of cabbage, and such things, 

 are commonly carried away, and are often given to the pigs 

 or chickens. Of course to dig such things into the soil 

 means that they may, before they rot, be very much in 

 the way of cultivation. Therefore it is better still to heap 

 them together for a year or more before they are brought 

 back to the garden. They then all rot together, and finally 

 turn into compost, a rich dark loam. This is the best of 

 plant food. 



The third method of supplying the soil with humus is to 

 use manure. Manure is, of course, only the food-stuff for 

 the horses and cows after it has been used to produce labor 

 or milk. Sheep and pig manure in the same way have come 

 from the soil, and can be returned to it. But like cornstalks 

 and other such things, manure is best after it has rotted for a 

 while, as it is then ready for the use of the plants as soon as 

 it is dug into the soil. Manure ought, therefore, to be heaped 

 together for some months, until it is rotted. 



But this heaping together of manure is not so simple a 

 matter as the piling of the stalks and leaves that are taken 

 from the garden. Even cornstalks are liable to "heat" and 

 to "burn," and therefore to spoil; but this seldom happens. 

 Manure, however (I am speaking of the most common kind, 

 horse manure), is certain to develop great heat, so that if left 

 alone it will actually become light and feathery, almost like 



