218 JOTTINGS OF A GENTLEMAN GARDENER 



Compounds of Magnesia : Those sometimes used by 

 gardeners are Magnesium carbonate and sulphate. In 

 solution, i oz. per 3-4 gallons of water is usually enough. 

 An application of either at the rate of about lb. for 

 every 2 or 3 square yards in the spring to soils of 

 ordinary loam has been found good, especially in the case 

 of roses. Magnesium carbonate in soils lessens evaporation, 

 and those containing much of it are cold and wet in winter. 



Compounds of Potash : The chemical name for Potash 

 is Potassium. The chief compounds are Potassium 

 carbonate, chloride, nitrate, phosphate, sulphate, and 

 sulphide. The first four are expensive, and the carbonate 

 and phosphate are also inclined to absorb moisture from 

 the atmosphere. Generally speaking, all plants are 

 benefited by an application of potash in some form or other, 

 but potassium nitrate should not be applied at all freely 

 to Lupins, Galegas, Sweet Peas, etc. Potash salts are 

 absorbed directly into the systems of plants by their roots, 

 for potash is found in the ashes of all plants. Hence it is 

 a necessity. Nitrate and phosphate of potassium act the 

 quickest ; they should be applied at the rate of I oz. 

 to every 3 or 4 gallons of water during the growing season 

 only. The phosphate is specially useful for Sweet Peas. 

 The carbonate, chloride (also known as muriate), and 

 sulphate of potassium are best applied in the form of powder 

 to the ground, in the winter, spring, or autumn. They may 

 be used on all soils except stiff clays. The rate of applica- 

 tion should not exceed 2 ozs. per square yard. Sulphate 

 of potassium can also be used in solution during the growing 

 season at the rate of Ib. per 8 gallons of water. The 

 sulphide is more of a disease curer than a fertiliser. Its 

 use has been described in Chapter XVII. Some writers 

 recommend that the soil around plants should be sprayed 

 with it in solution, and it is said to have some fertilising 

 value, but this seems doubtful. I myself advise that it 

 should be kept off the soil as much as possible. 



Compounds of Soda : The chemical name of soda is 

 sodium. The chief compounds used are the carbonate, 



