HOTBEDS 



53 



Hotbed Sash. — Two kinds of hotbed sash can be pur- 

 chased, the single-glass and the double-glass sash. They 

 can also be made by any local firm. When the sash are 

 constructed locally, specify emphatically that only the 

 most durable wood should be used and cypress or cedar 

 is preferred. Sash differ greatly in length and in width, 

 but the standard size is 3 x 6 feet. Sash of other sizes 

 are inconvenient to handle and possess no advantages 

 over the standard. The usual thickness of the sash is 

 about IJ inches, but this varies, and usually ranges from 

 If to 2 inches. The lighter sash are easier to handle but 

 the heavier ones are more durable and sustain less breakage. 



Fig. 13. — ^A good rack for hotbed sash. 



All sash should receive a priming coat of paint before 

 they are glazed. The cracks and the crevices should be 

 filled with paint in order to exclude all water, so that decay 

 will be lessened. Glass of the best quality should be pur- 

 chased. The lower grades of glass, as a rule, cause more 

 burning to the plants because of their many defects. 



The glass is placed into the frames by either lapping or 

 by butting. Lapping is the most popular and the method 

 that is usually recommended, because there is less leakage 



