24 VEGETABLE GARDENING. 



sown broadcast when the plants are perfectly dry or during a 

 hard rain. If it sticks to the leaves it is liable to burn them. 

 If sown during a hard rain it is quickly dissolved and washed 

 to the roots of the plants without injury to the leaves. It is 

 expensive and should never be used when a cheaper supply of 

 nitrogenous manure will do just as well. It may occasionally be 

 used to good advantage in water at the rate of one-half an 

 ounce of nitrate of soda to one gallon of water. Such a solution 

 will not injure the foliage and is of sufficient strength. 



The use of very large quantities of nitrate of soda on the 

 land has been found to make it necessary to continue using it 

 in large quantities, while if used at the rate given it is not 

 followed by such consequences. The supposed reason for this 

 is that so much nitric acid in the soil destroys the nitric acid- 

 forming ferments, and these must be slowly replenished before 

 the soil is able to continue yielding its ordinary supply of 

 nitrogen. 



Sulphate of Ammonia is a by-product from gas works and 

 contains about 20 per cent of nitrogen. It does not act as 

 quickly as nitrate of soda, but for late crops, to be applied dur- 

 ing warm weather, it is one of the best sources of nitrogen. 



Superphosphate is made by treating ground bone or nodu- 

 lar phosphate with sulphuric acid to render the phosphates 

 soluble. It is rich in phosphoric acid, and some kinds contain a 

 considerable quantity of nitrogen. They vary much in quality. 

 The better kinds are generally used at the rate of about 400 

 pounds per acre. 



Wood Ashes is rich in potash and a valuable fertilizer in 

 many cases provided it has not been leached; if it has been 

 leached it is practically worthless as a fertilizer, Ashes from 

 hard wood is much more valuable than that from soft wood 

 on account of its containing much more potash. Ashes is one 

 of the best fertilizers for fruit trees and plants. About twenty 

 bushels of unleached hard wood ashes is generally sufficient for 

 one acre, but much more may be safely used. 



Kainit. — Potash is also applied to the land in the form of 

 German Potash salts, a grade of which, known as kainit, is 

 very commonly used as a fertilizer. These salts are more or lessi 

 mixed with common table salt and other impurities and form 



