286 Fertilizers 



adapted naturally for market-gardening should either be 

 heavily manured, or should have been subjected to green- 

 manuring for a sufficient period of time to build it up in 

 vegetable matter. Owing to the cost, both in money and 

 labor, of supplying the food requirements through the use 

 of manures only, nowadays resort is made to commercial 

 fertilizers; these not only supply the total food, but 

 are capable of supplying them in such forms as to enable 

 the plants to absorb them at once. That is, there is no 

 necessity for any delay, in order that the plant-food con- 

 stituents themselves may be made available. Fertilizers 

 are therefore capable of supplying the needed require- 

 ments when other conditions are favorable, and may be 

 grouped into three classes; i.e. general, specific and 

 basic. That is, a general formula would be one that is 

 not made for any specific crop, but which contains both 

 soluble and insoluble forms of plant-food, with the idea 

 of building up the soil in the constituents, rather than 

 meeting the special requirements of any one crop. 



The specific formula is one made up for the purpose of 

 meeting a particular need of the crop at a particular time. 

 These will be noted through the discussions of the various 

 crops. A basic formula is one containing large quantities 

 of all of the best forms of plant-food to be used as a base 

 for supplying market-garden crops with their general 

 needs, with the idea that amendments may be made of 

 nitrogen, or of other constituents, as the conditions seem 

 to require. 



It might seem from the discussion thus far that for 

 these crops the recommendations as to methods of fertili- 

 zation might be briefly though fully expressed as follows : 



Apply a reasonable excess of all of the essential fertilizer 

 constituents to all of the crops. Nevertheless, because of 



