CHAPTER II. 

 GREENHOUSE CONSTRUCTION AND HEATING 



The purpose of this chapter is to discuss the principles of green- 

 house construction and heating. The details may be found in 

 special books, and in catalogs of manufacturers. 



Greenhouses vs. frames. Frames are admirably 

 adapted to vegetable forcing in the South, but for the 

 conditions of northern latitudes, greenhouses are vastly 

 superior for most purposes to frames. Their advantages 

 are numerous : (1) Heat for forcing purposes can be 

 generated cheaper by the burning of coal than by the 

 fermentation of manure. (2) All cultural conditions may 

 be better controlled or regulated in greenhouses than in 

 frames. (3) The labor expenditure on a given area is 

 usually much less in greenhouses than in frames. 

 (4) Shelter during inclement weather enables the em- 

 ployer of labor to follow a prearranged plan, and to utilize 

 the time of his workmen fully and economically. (5) In 

 the North it is not possible to grow in frames at mid- 

 winter such crops as tomatoes and cucumbers. In the 

 vicinity of all northern cities greenhouses are rapidly 

 taking the place of hotbeds and coldframes, not only for 

 the forcing of vegetables, but also for the starting of 

 early vegetable plants. Hotbeds and coldframes, how- 

 ever, have an important place in the vegetable forcing 

 industry, and their uses are discussed on page 387. 



Site and position of house. Any protection that can 

 be afforded by trees, hills, buildings or special wind- 

 breaks, without shading the house, will reduce the con- 

 sumption of fuel and aid in saving the structure from 

 damage by hard windstorms. It is advantageous to build 

 on level land, although gentle slopes are not objectionable. 



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