22 GARDENING FOR THE SOUTH. 



soluble in water containing alkaline matter in solution, 

 and in this state forms a portion, and sometimes an impor- 

 tant portion, of the food of plants. It is soluble silica, in 

 other words, dissolved sand, which the plant of wheat or 

 maize has extracted from the soil and deposited upon the 

 exterior of its stem, that gives the stalk or straw its stiff- 

 ness, and the lack of which in sufficient quantity subjects 

 it to the attacks of rust. Silica usually forms a small 

 proportion, too, of grains, legumes, and succulent roots. 



For garden purposes, the only kind of sand suitable is 

 that which is fine and has been rounded by moving water. 

 The angular particles of road sand form hard, impermea- 

 ble masses, and it should never be employed. (Lindley.} 



A loamy sand is a better soil than the preceding, and 

 contains from ten to twenty per cent of clay. These light 

 soils are best adapted to tap-roots and bulbs and for strik- 

 ing cuttings, while those heavier are better fitted for 

 plants with fibrous roots. 



A sandy loam contains between twenty and thirty per 

 cent of clay, while all soils containing from thirty to fifty 

 per cent of clay are classed as ordinary loams. 



In a garden designed for the cultivation of a variety of 

 plants, both a light and a moderately heavy soil are desira- 

 ble. But the best soil for general purposes is a loam of 

 medium texture, rather light than otherwise, arising from 

 a suitable admixture of the two, as they reciprocally cor- 

 rect the defects of each other. Where the other essen- 

 tials are present naturally, or added by man, such a soil 

 is suitable for the production of nearly all garden crops. 

 Any soil, by judicious culture, draining, and ameliorators, 

 or amendments, can be converted into such a loam. 



Lime in greater or less proportions is generally present 

 in soils, commonly as a carbonate. It is sparingly solu- 

 ble in water, and is especially, when combined with acids, 

 as in the sulphate (gypsum,) or the phosphate of lime 

 (bone earth,) an important portion of the food of our 



