PLANTS FOR WINDOW GARDENING. 79 



and free from mould or dirt ; cleanliness is a point too much 

 neglected. 



In some sections of our country, much difficulty is expe- 

 rienced in growing heaths ; the water containing salts in 

 solution which are fatal to the plant, and we know nursery- 

 men who have altogether abandoned their culture. This 

 seems the case in limestone countries, and we have noticed 

 that heaths, of the tender varieties, when watered with 

 "hard" water, grew sickly and soon died. The best plan 

 is to use only rain water, and pursuing this course no diffi- 

 culty will be experienced. It is a curious fact, that in its 

 native countries, the heath is never found in a soil of which 

 the substratum is lime or chalk. In England, -heaths are 

 always grown apart from other plants ; with us they occupy 

 the coolest part of the green-house. As a general rule, 

 nothing short of frost is too cold for them, and some 

 varieties will bear several degrees of frost without injury. 

 In the wild state, they are distributed over a vast range of 

 country, which accounts for the different temperatures the 

 varieties require ; the degree of cold adapted to each, must 

 be the lesson of experience. Among gardeners, heaths are 

 termed hard-wooded or soft- wooded; the former make only 

 a short growth each season, for example, E. Cavendeshii ; 



