100 PRACTICAL FLORICtJI/rtJRE. 



CHAPTER XIX. 

 MODES OF HEATING. 



Until the past few years the almost universal plan of 

 heating commercial greenhouses was by hot water, and 

 as that plan has yet many advocates, we herewith give 

 some of the leading points to observe when it is used ; 

 further on, we will refer to steam heating as now being 

 adopted in many large establishments. 



In heating by hot water, it is important that the work 

 be given to some reputable firm, whose knowledge is such 

 as will enable them not only to judge what is the proper 

 capacity of the boiler for the number of pipes to be used, 

 but also hew many pipes are necessary to be used for the 

 surface of glass to be heated. Men who have done a 

 large business in heating greenhouses, have far better 

 opportunities for knowledge in this matter than the aver- 

 age gardener or florist ; and if those erecting greenhouses 

 have not had extensive and varied practice, they had 

 better be guided by the men who make a business of heat- 

 ing, as the want of the requisite knowledge of these 

 matters often works serious mischief. Of course, the 

 size of the greenhouse or greenhouses to be heated must 

 determine the capacity of the boiler required ; but the 

 boiler being properly apportioned to the length of pipe, 

 the following data, used in our own establishment 

 (which is mostly heated by hot water), may be useful. 

 In our houses, which are twenty feet wide and one hun- 

 dred feet long, when a night temperature of seventy de- 

 grees is required in the coldest weather, ten runs or rows 

 of four-inch pipe, five on each side, are required ; when 

 sixty degrees is wanted, eight runs of pipe, four on each 

 side ; when fifty degrees is wanted, six runs of pipe will 

 be needed; and when only thirty-five or forty degrees is 



