FLUE -HEATED HOTBEDS 85 



tions for the making and management of forcing- 

 houses may be found in Taft's "Greenhouse Con- 

 struction" and in Bailey's "Forcing -Book." 



Close attention is required in the management 

 of hotbeds, to insure that they do not become too 

 hot when the sun comes out suddenly, and to give 

 plenty of fresh air. Ventilation is usually effected 

 by raising the sash at the upper end and letting 

 it rest upon a block. Whenever the temperature 

 is above freezing point, it is generally advisable 

 to take the sash off part way, as shown in the 

 central portions of Fig. 78, or even to strip it off 

 entirely, as shown in Fig. 76. Care should be 

 taken not to water the plants at nightfall, espe- 

 cially in dull and cold weather, but to give them 

 water in the morning, when the sun will soon 

 bring the temperature up to its normal state. 



The most satisfactory material for use in hotbed 

 and coldframe sash is double- thick, second-quality 

 glass ; and panes which are twelve inches wide 

 are ordinarily wide enough, and suffer compara- 

 tively little in breakage. For coldframes, how- 

 ever, various oiled papers and water -proof cloths 

 may be used, especially for plants which are 

 started little in advance of the opening of the 

 season. When these materials are used, it is not 

 necessary to have expensive sash, but rectangular 

 frames are made from strips of pine seven -eighths 

 inch thick and two and one -half inches wide, 

 halved together at the corners and each corner 



