VERTICAL FARMING 



45 



exclude the air and smother out the good forms, but permit the 

 harmful bacteria to grow at will. While too much water is 

 bad for them, too little water also retards their work. A good 

 moist soil, just about what the plants want, is their favorite 

 in short, a well drained soil. Most of them need a supply of 

 organic matter, such as partly decayed plants or animals. This 

 is also just what the plants want. Another one of their desires 

 is for even tempered soil, where the changes are not too sudden 

 from hot to cold. Here again they agree absolutely with the 

 plants. In fact the beneficial bacteria and plants seem to be 

 such good friends and neighbors that anything that benefits one 

 equally benefits the other, and if one feels sick, the other wants 

 the doctor also. 



In keeping up the bacterial activities care in turning under 

 green manures or additions of litter or manure is always repaid 

 many fold. These additions of humus forming material also 

 assist greatly in maintaining the needed moisture supply as 

 humus has a wonderful power of absorbing and holding water 

 and also assists in granulating the soil. 



More About Nitrogen. Free nitrogen is everywhere. The 

 air over a single acre contains about 75,000,000 pounds of this 

 peculiar element. To buy a pound will cost from 15 to 20 cents. 



TWO SOURCES OF NITROGEN 

 HOME TRAPPED BY LEGUMES BOUGHT AT GREAT COST 



