160 AGRONOMY 



thoroughly tramped down. Over the pit of manure a layer of 

 good soil 6 inches deep should be spread, and in this the 

 plants are grown. The hotbed frame is made of boards, and 

 the roof, which is made of one or more hotbed sashes, should 

 slope toward the south. The front of the bed may be 6 inches 

 or 1 foot high and the back 12 to 20 inches. Hotbed sashes 

 are 3 by 6 feet in size, and the frame is made about 6 feet 

 wide and long enough to take one or more sashes. Old win- 

 dow sash may be used if hotbed sash are not at hand. When 

 the manure is first put into the pit and the sashes put on, 

 the heat often rises too high for plant growth. Seeds should 

 not be planted until the temperature at midday falls below 



90. The frame is usually 

 banked up on the outside 

 with manure as an addi- 

 tional protection from the 

 sfll cold, and on very cold 



nights the glass should be 

 covered by mats, old car- 



Fio. 112. A hotbed showing the details ^ QT a j of straw, 



of construction 



Hotbeds are sometimes 



made upon a level pile of manure placed on the surface of 

 the ground. In this case the manure should project beyond 

 the frame at least a foot on all sides. The heat in a hotbed 

 is not sufficient to carry it through the entire winter, and its 

 use is usually confined to the late winter and spring. In the 

 Northern states the hotbed is not begun much before the 

 middle of February, and in many cases the middle or end of 

 March is early enough. In managing the hotbed care should 

 be taken to give the plants air whenever the weather is favor- 

 able. This may be accomplished by lifting the lower end of 

 the sash and placing a block under it, or on fine days the sash 

 may be shoved part way off the frame. Plenty of air tends to 

 make the plants sturdier. 



