CHEMICAL FARMING 219 



crop, which otherwise would be required to convert 

 the food chemicals into solution. 



Every plant requires sunshine (to manufacture its 

 food) and a firm support to hold it, usually in a ver- 

 tical position, and moisture to convert its food into 

 an easily assimilable form. If these three require- 

 ments are supplied in their best form, including air, 

 nature will take care of the results bountifully in 

 blossoms or food. 



Among the necessary chemicals now known are 

 these four: Ca(NO 3 ) 2 , KNO 3 , MgSO 4 , KH 2 PO 4 , 

 which might be classed as fertilizing elements and 

 will be found in the ash of most plants in approxi- 

 mate proportions of 6-42-1, although the quantities 

 may vary considerably according to the type of the 

 plant. It is not to be expected that a cucumber and 

 a tomato will need exactly the same dishes of food. 

 In forcing a plant in a nutrient solution, the above 

 four elements may be given in varying quantities, as 

 one would give fertilizer in soil grown plants, with 

 the same good or bad results. Of the dozen or more 

 other elements fed the plants the proportions must 

 be more accurately controlled, as a surplus of any 

 one of them may produce disastrous results. The 

 safe quantities are so small it is difficult to weigh 

 them except in a large quantity, then dissolved in 



