60 THE PRINCIPLES OF FLORICULTURE 



In constructing a bed to be heated from the green- 

 house or house cellar, a sub-frame is first built. 

 This is about four inches thick, two to three feet in depth, 

 and is made of wood, brick, concrete or other material. 

 An extension of this frame is built above ground, and on it 

 the sash rests. To give plenty of head room for the plants, 

 the frame is built about six inches above ground on the 

 south side and about twelve inches on the north side. 

 The sub-frame is filled to within about one foot of the top 

 with porous soil which insures perfect drainage. Six 

 inches of well-enriched loam is then placed over the subsoil. 

 This brings the soil twelve inches from the frame on the 

 south side and eighteen inches on the north side. Plants 

 are set directly in this surface loam. The heating pipes 

 may be run along the foundations of the house. The 

 frames should be protected with mats and shutters on 

 cold nights. These should be removed every bright day, 

 and especial attention given to ventilation, or the plants 

 will smother. The frame should be kept free from snow. 



The term hotbed generally means a frame constructed 

 as the one just described, but one warmed artificially by 

 means of heat generated from fermenting stable manure. 

 The manure acts only as a heating agent, not as a fertilizer. 

 In selecting material for constructing the frame, it is well 

 to decide on the most durable material even if the first cost 

 is somewhat greater. 



For permanent frames, concrete is the most durable. 

 The sub-frame is eight inches thick and is made three 

 feet below grade. Above grade, the ends of the frame are 

 five inches thick and the sides four inches. The forms 

 are first placed, and into these forms is poured the con- 

 crete. Hemlock boards, one by twelve inches, are used 

 for the forms, with two by four inch studding for the 



