32 SOIL. 



of course, that where soils showing so much differ- 

 ence in structure are used the plants in each case 

 have different sets of factors to which they must 

 adapt themselves, and in doing this they may be so 

 modified as to materially affect the development of 

 the flowers. 



Soils of both the heavy and moderately heavy 

 types are found in many places and if they do not 

 occur naturally the desired effects may be approxi- 

 mated by combinations of light and heavy soils. 

 We have never found it satisfactory to lighten 

 heavy soil by mixing in sand alone. This takes 

 away the life of the soil and plants never succeed 

 so well in it as when the desired conditions are 

 produced by mixing a heavy and a light soil. For 

 example, we may have in one part of a field a soil 

 containing fifteen to twenty per cent of clay and 

 in another one containing four or five per cent. 

 By mixing these two soils in equal proportion a 

 combination is effected which, other conditions 

 being equal, will prove better for violets than 

 either soil used alone. 



Of course it must be remembered that the 

 conditions for plants under glass are different 

 from those out-of-doors. Outside the plant has 

 to take what it can get in the way of water, air, 

 and other important conditions for growth, while 

 inside these are in a measure made to order by the 

 grower himself. It follows, therefore, that even 

 where the soil is not what it should be the grower 



