l6 THE CULTURE OF POT-PLANTS 



lose it. A window, however, has its disadvantages. Every 

 time it is opened the plants in or near it are in a draught, 

 and if the door of the room is open at the same time the 

 effect is deadly. Moreover, the changes of temperature are 

 greater near a window than they are farther away. In winter 

 the cold air outside impinging on the glass cools it, and thus 

 cools the air in contact with it inside, producing currents of 

 a low temperature — so low during severe frost that the plants 

 exposed to them may be killed. Of course the effect is 

 lessened when the blinds are drawn down between the plants 

 and the glass, but at such times it is much safer to remove 

 to a warmer position all species which are not quite hardy. 



The chief points in this connection may be repeated 

 briefly : — 



Clean by washing or spraying the foliage of all pot-plants 

 in rooms at least once a week. 



Stand them out in the open air when the opportunity 

 occurs, but not, if they have delicate leaves, in strong 

 sunshine. 



Keep them well away from fires and lamps. 



Never let them be in a draught. 



If they are in a window, draw down the blind between 

 them and the glass in the evening in winter ; and if the 

 weather is very cold, remove them further into the room. 



If any should be frozen, they should be treated as advised 

 in the next chapter. 



