30 SOIL. 



CHAPTER II. 



THE SOIL. 



The soil forms the basis for all work in plant 

 growth and it is proper therefore that it should be 

 discussed first. Violets will grow on almost any 

 soil, but to obtain the best results it is necessary 

 to pay attention to certain important characters of 

 the soil, particularly those relating to its physical 

 properties. The importance of the relation of the 

 physical properties of the soil, that is, texture, 

 temperature, and moisture, to plant growth is not 

 fully appreciated. By texture is meant the 

 character of the particles which make up the soil, 

 while structure has to do with the arrangement of 

 these particles and their relation to each other. 

 The particles, or grains, of which soils are com- 

 posed vary greatly in size, and to distinguish them 

 they have received certain conventional names, 

 such as clay, fine silt, silt, fine sand, sand, etc. 

 The clay particles are extremely minute, silt grains 

 are larger, and so on until we have coarse sand or 

 gravel, with grains l /25 to 12 of an inch in diameter. 

 Upon the amounts of the various constituents, 

 i. e., clay, fine silt, silt, fine sand, etc., depends 

 the porosity of the soil, the readiness with which 



