CHAPTER VI 

 HEATING THE RANGE 



GREENHOUSE heating is a problem which requires very 

 careful study. Much thought and investigation has been 

 given the subject, still, in the opinion of the best growers, 

 much remains to be learned. 



72. Difficulties in heating greenhouses uniformly. - 

 Greenhouses are exceedingly difficult structures to main- 

 tain at a given temperature because their character 

 makes them especially susceptible to variations from out- 

 side heat or cold. Conditions are such in greenhouses 

 that a variation of a few degrees in temperature may so 

 retard the development of the plants, that a great financial 

 loss to the grower is the result. If the change of tem- 

 perature is great, it means death to the plants. Green- 

 houses as now constructed are so much larger than in 

 former years that it has become necessary to install 

 systems of heating which will be under perfect control 

 at all times, and a uniform temperature thus maintained. 



73. Methods of heating. Commercial ranges of the 

 present day are heated by steam or by hot-water. In 

 the larger number of cases, steam is used. 



74. Comparative merits of hot-water and steam heat- 

 ing. In the early history of the industry, practically 

 all greenhouses were heated by hot-water. The ranges 

 were small and hot-water was found to be more economical. 

 Hot-water heat has always been considered to be less 



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