Forcing -hills 



69 



off in them as they cool, thus, perhaps, obviating the 

 necessity of transplanting to other frames. 



Span-roof coldframes (Fig. 19) are very useful, as 

 they allow of better and more uniform conditions for 

 the growing of plants than the ordinary frame. They 

 are covered with hotbed sash laid on a framework, 

 and the sashes pulled down from the top for venti- 

 lation. They are essentially forcing -houses, however, 

 and the discussion of them is foreign to the purpose 

 of this volume. 



Forcing-Mils. — A forcing- 

 hill is an arrangement by 

 means of which a single plant 

 or a single hill of plants may 

 be forced where it perma- 

 nently stands. It is a small 

 coldframe. This type of forc- 

 ing may be applied to per- 

 ennial plants, as rhubarb and 

 asparagus, or to annuals, as 

 melons and cucumbers. Fig. 20 illustrates a common 

 method of hastening the growth of rhubarb in the 

 spring. A box made with four removable sides, two of 

 which are shown in end section in the figure, is placed 

 around the plant in the fall. The inside of the box 

 is filled with straw or litter, and the outside is banked 

 thoroughly with any refuse, to prevent the ground from 

 freezing. When it is desired to start the plants, the 

 covering is removed from both the inside and outside 

 of the box, and hot manure is piled around the box 

 to its top. If the weather is still cold, dry, light leaves 



