THE GARDEN PRIMER 



But the ideas about this food are very vague; "what 

 plants eat" is an untold tale, mysterious, almost chimer- 

 ical to the practical mind accustomed to seeing before 

 believing. Let us see if we can't straighten this out a 

 little and come to a real comprehension of plant feed- 

 ing; then fertilizers will not seem so deadly dull and 

 uninteresting, and incomprehensible. 



The food of plants consists of thirteen "chemical 

 elements." Nine of these are taken by the plant 

 directly from the soil these are the pure mineral plant 

 foods three are taken from water and from air, and the 

 thirteenth and last is taken principally from decaying 

 organic matter in the soil. 



In order to understand this quite clearly let us 

 stop just here long enough to take a look at the chemical 

 classification of the soil, spoken of in a previous 

 chapter. Soil is made up of mineral matter and organic 

 matter two forms that are of course, widely different 

 and to get at this composition of it in the simplest way 

 possible we will follow the suggestion of one of the 

 Department of Agriculture experts and magnify a cubic 

 inch of soil, in the imagination, to a cubic mile and 

 then look it over. It becomes very vivid, and the 

 processes going on in it are plainly revealed, under such 

 examination. 



It will look like a mass of rocks and stones vary- 

 ing from the size of a pea to boulders several feet in 

 diameter. These are the mineral particles in common 

 parlance the "dirt" which predominate and form the 

 foundation of all soil. Among these rocks and stones, 



30 



