PROJECT 11 



THE CONSTRUCTION AND USE OF HOTBEDS AND COLD FRAMES 



Materials. Window sashes and lumber ; spade ; soil thermometer ; manure prepared as explained 

 below, and angle irons and bolts. 



Directions. The hotbed should be 6' wide, located on the south side of a building and on high 

 ground. In the fall, before the ground is frozen, dig a pit 18" deep and a few inches larger than the 

 outside dimensions of the frame. If the bed is to be set early, that is, before the middle of March, 

 it is better to dig the pit 2' deep. Construct the frame as shown in Fig. 160. Window sash may be 

 used to cover the frame. Double glass sash is best, as it avoids the necessity for extra coverings 

 during cold nights. 



Gather fresh horse manure, mix it with one fourth its bulk of straw or leaves, and put it in a compact 

 pile to heat. After it has heated for three days fork the heap over. On the fifth day repeat this opera- 



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Hi'dtiiii/ Manure 



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Fig. 160. Concrete hotbed 



tion, and on the eighth day place the manure in the pit, tamping thoroughly as it is placed, and wet 

 it thoroughly. Fill the pit to within an inch of the surface. Put the frame in place and bank earth 

 or heating manure around the outside to retain the heat and shed surface water. 



Supply a layer of rich garden soil about 6" deep in which the plants are to be grown. Moisten 

 the soil and place the sash on the bed. There will be a gradual rise in temperature at first, and later 

 the temperature will slowly drop. When the temperature of the soil falls below 90 F., plant the 

 seeds. From this time keep proper temperature by ventilation and water the plants as needed. 



Plant such crops as later may be transplanted in the school or home garden. 



Record all results as : variety and number of plants produced ; daily temperature of the hotbed ; and 

 length of time required for the germination of the different kinds of seeds and the rate of growth of the 

 plants of each. 



After serving its purpose the hotbed may be used as a cold frame. A cold frame is like a hotbed 

 except that there is no manure pit and no source of heat except the sun. The soil layer should be the 

 same, and the covering may be sash, as in the hotbed, or it may be cloth if the season is well advanced. 

 Record the crops produced and the results obtained, and compare the value of a cold frame with that 

 of a hotbed. 



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