WATERING AND WATER. 197 



should be provided with a valve, so that it may be turned off 

 when not required. 



The best water it is possible to use for plants in general, 

 and for hard-wooded greenhouse plants in particular, is soft 

 or rain water ; and ample convenience should be provided to 

 store it for use during summer, when long drought may be 

 expected. Water obtained from springs, usually called hard 

 water by gardeners, is very injurious to plants, on account of 

 its containing an excess of the salts of magnesia or of Ume, 

 the prejudicial effepts of which will soon become apparent, if 

 applied to Ericas and many other hard-wooded plants ; and 

 always be careful in watering plants not to allow the water to 

 fall on too heavily, as it wiU disturb the roots, and often 

 cause the plant to get into an unhealthy state. 



