Forcing Houses for Carnations 



These narrow houses were, as a rule, poorly heated, and frequently 

 inadequately ventilated, as growers often sought to economize in coal by 

 keeping the houses closed during cold weather. In order to produce the 

 best results in the forcing of any flowering plant under glass during the 

 winter months, it is essential to provide for the admission of the greatest 

 amount of sunlight possible, as well as to furnish sufficient ventilation to 

 keep the plants in a pure, clean, normal atmosphere. 



The increasing demand for carnation blooms of larger size, with longer 

 stems, has forced the carnation grower to constant effort and study, with 

 a view of improving, not only his methods of growing, but the structures 

 in which the plants are cultivated. 



The various forms of carnation houses now in general use may be 

 divided into three types : the even span, which may be built with a ridge 

 running north and south, or with the ridge running east and west ; the 

 three-quarter, or long span to the south, which is always built with the ridge 

 running east and west ; and the short span to the south, which might be 

 termed the long span to the north house, which is also built with the ridge 

 running east and west. 



Exhaustive trials with forcing houses have demonstrated that for forcing 

 purposes wide houses are preferable to the narrow houses that were exclu- 

 sively used up to a comparatively recent period ; consequently, the most 

 modern structures have been built from 28 ft. to 30 ft. wide and upward, 

 instead of 16 ft. to 20 ft. The length of these houses has also been increased 

 from 50 ft. to 100 ft., up to 300 ft., and even 400 ft. The advantages found 

 with these wide houses are many. In the first instance, the cost of the 

 structure per foot of bench surface covered is relatively less than is the case 

 with the narrow house. Secondly, the cost of heating and maintaining the 

 bench surface at the growing point is relatively no greater in the wide house 

 than in the narrow one, and by some growers is claimed to be less. The 

 increased volume of air contained in the larger houses maintains a more 

 uniform temperature than is possible with a narrow house. The oscillation 

 of temperature is sensibly less in the wider house, and the larger volume 

 of air cools off more slowly than in the small houses. True, when cool, 

 the larger houses require a greater expenditure of coal to raise the tempera- 

 ture to the proper point, but once the proper degree of heat is obtained, it 

 is relatively easier to maintain it than is the case where a smaller body of air 

 exists. In other words, it seems that the evaporation of heat is more nearly 

 in proportion to the glass surface exposed, than to the volume of air con- 

 tained under that glass surface. Be this as it may, it appears to have been 



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