POT-PLANTS IN ROOMS 7 



watered in this way. As the outside soil has only a thin layer 

 of moss between it and the air, it soon gets excessively dry. 



Only plain water should be used when the soil is very 

 dry. It should not contain any sort of artificial fertiliser, 

 for the dose, when not diluted by any other moisture in the 

 soil, might be excessive ; and even if it were not, the object 

 of feeding is to supply the material of growth, and growth is 

 impossible when the plant is in a flaccid condition. It must 

 first be restored to health by replacing the water it has lost, 

 and if the loss has been serious, it should be kept for a time 

 in a close, still atmosphere and in a shaded position, so as to 

 lessen the strain on its vital functions. In fact, it is tem- 

 porarily in the same condition as a cutting, and should be 

 treated in the same way. 



The chief points as regards watering may be summed up 

 thus : — 



Give water not by rule, but in accordance with the 

 requirements of the plants. 



Never merely sprinkle the surface. When the soil 

 becomes fairly dry, give enough to moisten it all thoroughly, 

 if necessary immersing the pot in a pail. 



In winter very little water is necessary, especially for decidu- 

 ous species. Some plants, such as cactuses, do not require any. 



When the soil is very dry, no fertiliser should be dissolved 

 in the water. 



Water which contains lime — hard water — should never be 

 given to such plants as azaleas, heaths, and rhododendrons. 



For all plants, rain water is the best. 



It should never be colder than the atmosphere of the 

 room. 



Provided with plenty of water and a suitable temperature, 

 plants are in a position to make use of what food materials 

 are available ; but if growth is to be satisfactory, these materials 

 must be of the right kinds and in the right quantities. It is, 

 therefore, necessary that suitable soil should be used, that it 

 should be kept in good condition, and that the ingredients 

 abstracted from it during the process of growth should be 

 replaced. 



