SASH-BED CONSTRUCTION 21 



On top of this is placed a frame. The ad- 

 vantage of this form of bed is that the frame 

 settles with the manure, thus keeping the 

 plants always the same distance from the 

 glass. They are also warmer on account 

 of the greater quantity of manure used. 



Manure for Heating. Horse manure is al- 

 most universally used in hotbeds, the pro- 



Fig. 8. Usual type of concrete hotbed 



portion being about two parts solid excre- 

 ment to one part straw or leaves. Manure 

 which contains shavings is not satisfactory. 

 Preparation is made 10 or 12 days before the 

 beds are wanted. The manure must be fresh- 

 ly made and if not moist is dampened, prefer- 

 ably with warm, though not hot water. 

 More than enough manure to fill the pit is 

 provided, for it will shrink somewhat in vol- 



