34 



VEGETABLE FORCING 



Glazing. Greenhouse glass is usually lapped when 

 laid, although it is sometimes butted. The glazing is 

 performed more rapidly when the glass is lapped, and it 

 is much easier to replace broken panes. There is also less 

 leakage when the panes are lapped. The chief objection 

 to lapping is that more or less dirt and soot collect be- 

 tween the laps. Butted glass must be set with very great 

 care in order to make the joints water-tight. A variety 

 of glazing points is on the market. 



Previous to glazing, all wood parts of the greenhouse 

 should be primed with one coat of paint. The sash bars 



Fig. 21. Bench with pipe frame support. 



should be perfectly dry before putty is applied, and the 

 putty should be of the best grade and kept soft by the use 

 of linseed oil. It may be applied with a putty bulb, 

 machine or knife. It is most convenient to begin at the 

 end of the house and the eaves, and then to work up 

 towards the ridge until the first row is completed, next 

 laying the second row, and so on until the roof is finished. 

 Sometimes the putty is applied on the outside of the 



