GRASSES GREENHOUSE 123 



bromus, eragrostis, and pennisetum. Seeds of these and 

 of others are sold by seedsmen. With ordinary treatment, 

 they thrive in any garden soil. 



For notes on sod -making, see Lawn. 



Greenhouse. In America the word Greenhouse 

 has come to be applied to all kinds of glass-houses in which 

 plants are grown. Originally the word was applied to those 

 houses in which plants are merely preserved or kept green 

 during the winter. Other types of glass-houses are the con- 

 servatory, in which plants are displayed ; stove or hothouse, 

 in which plants are grown in a high temperature; the prop- 

 agating pit, in which the multiplication of plants is carried 

 forward ; and the houses which have various temperatures, 

 as cold, cool and intermediate. The principles which under- 

 lie the construction and management of glass-houses are too 

 extensive to be discussed here. The reader should refer to 

 special books on the topic. For the general subject, Taft's 

 "Greenhouse Construction" and "Greenhouse Management" 

 are excellent. For particular applications to floriculture, 

 Hunt's "How to Grow Cut-flowers" is a standard work. 

 For applications to the forcing of vegetable crops, Bailey's 

 "Forcing-Book" may perhaps be consulted. 



The smaller the glass-house the more difficult it is to 

 manage, because it is likely to be more variable in tempera- 

 ture, moisture and other conditions. This is particularly 

 true if the house is a small lean-to against the south side of 

 a dwelling house, for it becomes very hot at midday and 

 comparatively cold at night. In order to moderate the heat 

 in these little houses, it is ordinarily advisable to use ground 

 glass for the roof or to whitewash it. The house conserva- 

 tory may be heated by a coal stove, but the best results are 

 rarely to be attained in this case. A stove is likely to leak 

 gas, and the temperature is more or less uneven. The best 

 results are to be attained when the conservatory is heated 

 by steam or hot water, piped in the modern fashion with 

 wrought iron pipes, which go together with threads. If the 



