24 THE BOOK OF THE GREENHOUSE 



knuckles. If the result is but a dull response, such as 

 one would get from tapping any solid body, no water 

 is required ; but if a hollow or slightly ringing sound 

 be produced, then the time for watering has come. 

 Should the ringing be accentuated, the plant should be 

 plunged in a pail of water and left there for a few minutes 

 to absorb as much as it can and to allow the water to 

 reach the middle of the ball, dryness of which is not 

 easily remedied by giving water in the usual way 

 through the spout of a watering-pot. The avoidance 

 of such excessive dryness as this, however, should be 

 one of the chief cares with the grower, as fatal results 

 of such neglect are to be expected. 



Many hard-wooded plants being averse to lime in any 

 form, provision should always be made for a supply of 

 soft water, and if this is not sufficient for all the plants 

 grown in the greenhouse it should be specially reserved 

 for those of this class. 



Overhead syringing is not often necessary, though for 

 a time, during the early period of new growth, a dewing 

 of soft water appears beneficial, and the plants certainly 

 seem to thrive under the influence of the heavy night 

 dews which they experience during fine weather when 

 growing in the open air. 



Insect pests do not as a rule give much trouble to 

 hard-wooded plants which are well looked after and well 

 treated, but there are some which trouble certain plants, 

 as for instance : Thrips are partial to Azaleas, Scale in 

 variety to Camellias, White Scale to Neriums (Oleanders), 

 Red Spider to Pimelias, and some of these plants have a 

 common enemy in them all. Needless to say, the plants 

 cannot thrive under attacks from these pests which sap 

 their life blood and choke their pores with filth. In 

 the matter of dealing with insect pests, however, the 

 present day grower lives in comparative joy, for science 

 during the past few years has produced many insecticides 



