CHAPTER VI 



THE VEGETABLE FORCING INDUSTRY 



BEFORE there was an important com- 

 mercial vegetable industry at the South, 

 there grew up a demand for crisp fresh 

 vegetables out of season. The gardeners about 

 the larger towns and cities of the North felt 

 this demand and set about meeting it as best 

 they could by means of hotbeds and cold frames, 

 but these were makeshifts at best and, although 

 successful for certain seasons of the year, they 

 left a long interval during midwinter when the 

 markets were bare of fresh garden products. 



As a result of the perfection of appliances 

 for heating glass structures, both by hot water 

 and by steam, it became possible to heat large 

 greenhouses satisfactorily. About this time the 

 clumsy frame structure, covered by movable 

 sash, gave way to the sash bar construction 

 and the modern forcing house was evolved. 

 Small glasses were replaced by large ones, 

 ventilating apparatus came into general use, 

 and the gardener became master of the ele- 

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