CHAPTER III 
SOILS 
Selection.—The utmost care should be exercised in the 
selection of soil for vegetable forcing, for however skillful 
the grower may be, he cannot expect complete success 
without the most favorable soil conditions. Unfor- 
tunately, we possess very little basic information about 
greenhouse soils, for they have not been studied to any 
great extent by scientific investigators. Our knowledge 
of them and their management has been deduced mainly 
from the experiences of successful commercial growers. 
Greenhouse soils abnormal.—The soils in most of the 
greenhouses devoted to vegetable forcing and to flori- 
culture are abnormal in structure, color, organic content, 
and probably in chemical composition. Even the texture 
is often modified by the addition of sand and ashes. So 
great are the alterations in some instances that the soils 
would not be recognized as belonging to any particular 
classified types. The greenhouse grower strives to 
establish the best and most perfect soil conditions, and 
the returns usually justify the expenditure of as much 
time and money as may be required to accomplish this. 
His problem of soil management is radically different 
from that of the general farmer, who may gradually im- 
prove his land from year to year, while the greenhouse 
grower should secure the maximum production within a 
year or two. The glass structure over an acre of land 
represents a large investment. This fact and the cost of 
fuel and other operating expenses make it imperative to 
spare no effort in providing the very best soil. 
Texture.—The texture of a soil is characterized by the 
proportion of the different-sized mineral particles which 
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