CONSTRUCTION OF GREENHOUSES 



125 



build with a space of 10 to 15 feet between the houses. 

 This not only renders gutters unnecessary, but avoids 

 shading in the houses and gives room for snow. 



180. Glass. It is most economical in the end to use 

 glass of high quality. Single strength was in common 

 use 10 or 15 years ago, but experience has taught green- 

 house men that anything inferior to A double strength 



FIG. 28. A COMMON FORM OF GREENHOUSE BRACING 



should not be used. The lighter and inferior grades not 

 only sustain greater breakage from hailstones, but the 

 imperfections may cause injury to the plants by burning. 

 Small glass was used extensively in the construction 

 of the old-style houses, which necessitated placing the 

 sash bars close together. This condition increased the 

 cost of construction and decreased the amount of light 

 that could enter. For many years 10 x 12-inch glass was 



