296 YARD AND GARDEN 



plants. It is valuable, however, as a medium 

 in which to root cuttings, for fungus diseases 

 seldom develop in such a soil, and, as the 

 plantlets, until their roots have sprouted, re- 

 quire little nourishment, outside of what is ob- 

 tained through the water applied, no soil is 

 better adapted to the purpose than that which 

 is sandy. 



Clay soils contain only a small proportion of 

 sand — from to 20 per cent. — and, unless in 

 some manner more sand is added, it is of little 

 value for plant raising. It contains an abun- 

 dance of plant food, but, owing to the fact that* 

 the food is unavailable, plant life can not 

 thrive in such a rooting medium. The small 

 particles of soil are tightly compressed in clay 

 and, though these absorb moisture, they give 

 it off reluctantly. Roots suffer not only on 

 this account but also through their inability to 

 penetrate into the compact mass. 



Humus is decayed vegetable matter and may, 

 in turn, be divided into two classes. The first 

 is composed of vegetable matter which has 

 come to decay in dry earth and is known as 

 leaf-mold. The second is composed of vegeta- 

 ble matter which has decayed under the water 

 of bogs or swamps and is known as peat. Both 



