THE HOTHOUSE OR FORCING GRAPERY. 



255 



reaching the roots, as to apply heat to the vines inside 

 while the roots are frozen would seriously injure them. 

 For very early forcing, when the vines are started as 



Fig. 81.— ELEVATION OF FBONT OF FOKCING GRAPERY (iN PART). 



cr. 



TZT^r 



Fig. 82.— SECTION OF FORCING GRAPERY. 



early as January, it is usual not only to put on covering 

 enough to secure from frost, but also to slightly ferment, 

 60 as to throw some warmth into the border. Ko matter 



