SOIL, MANURES AND WATERING. 363 



tings, or to be repotted. For plants grown either in 

 shallow or in solid beds, the addition of bone meal to the 

 soil, both at time of planting and at intervals during the 

 season, will be of value. One quart of pure, fine ground 

 bone to a bushel of soil will answer for this purpose, but 

 two or three times as much can be used for seed boxes, 

 or for repotting. Ground bone furnishes about twenty 

 to twenty-five per cent phosphoric acid, of which less 

 than one-half per cent is soluble, and about six per cent 

 is reverted (available to plants). It also contains about 

 four per cent of nitrogen. There is, however, a consid- 

 erable variation in the amount of the constituents. 

 Mildly acidulated bone, if used at all, should be first 

 carefully tested. 



Bone superphosphate is made by dissolving bones in 

 sulphuric acid, thus rendering nearly all the phosphoric 

 acid available to the plants. If used carefully, it is of 

 value in the garden and for deep beds, but as the com- 

 mercial brands generally contain some free acid and pot- 

 ash, its use by the florist in the greenhouse cannot 

 be recommended. 



Dissolved bone black consists of the refuse bone 

 charcoal from sugar refineries and other sources, dis- 

 solved in acid, and ground. It is of varying strength, 

 and contains all the way from fifteen to twenty-five per 

 cent of phosphoric acid. The phosphorus is in a solu- 

 ble form, and were it always free from sulphuric acid, it 

 would be preferable to raw bone. It should be used 

 with great care in pots or shallow beds, but when it can 

 be thoroughly mixed with the soil in the garden or in 

 deep beds, it forms a valuable source of phosphoric acid. 

 When used in repotting soil, or in shallow beds, one 

 pound to the bushel can generally be used with safety, 

 while half that quantity will be as much as any crop will 

 need.' It is, however, particularly desirable as a top- 

 dressing, using perhaps one pound to twenty square feet 



