180 THE PRINCIPLES OF FLORICULTURE 



is effected which, other conditions being equal, will prove 

 better for violets than either soil used alone." 



146. Sweet pea soil. Soil suited for violet culture is 

 also well adapted for growing sweet peas under glass. 



147. Rose soils. An ideal rose soil is one which con- 

 tains about twenty per cent of clay, but the real 

 value of such a soil depends also upon the percentage 

 of silt and sand which it contains, as well as upon the 

 amount of decayed organic matter. There should be suffi- 

 cient sand in the soil, so that it is porous and not so com- 

 pact that the roots cannot penetrate it easily. A soil 

 which contains more than sixty per cent- of silt and clay, 

 is known as a clay loam. 



148. Soil for other crops under glass. Carnations, 

 chrysanthemums and bedding plants are not so particular 

 in regard to soil conditions as are many of the other flo- 

 rists' crops. There are, however, certain soils which are 

 better than others for these crops. Light, sandy soils 

 are detrimental to plants because they retain so little 

 water. Soils with a large percentage of clay are difficult 

 to work, and are characterized as " cold soils." When 

 crops require summer culture out of doors, as do carnations, 

 it is essential that the soil naturally contain a proper 

 proportion of sand, silt and clay. 



149. Organic matter in soil. Aside from the mineral 

 particles, practically all soils contain more or less organic 

 matter. The source of this comes largely from plant 

 bodies in various stages of decomposition, but a certain 

 percentage is derived from animals. These animals are 

 mostly of the so-called lower forms. 



150. Forest soils. Forest soil contains large amounts 

 of leaf tissue in various stages of decomposition, and this 

 is known to the gardener as leaf-mold. Soils in which 



