276 NATURE-STUDY 



it up well, and covering it with a glass roof. An unused 

 storm window may be used for this. By that time storm 

 windows will not be needed on all the windows, and one 

 can be taken from the school. Plant seeds in the frame 

 about the first week in March or later. Keep the soil 

 well moistened. The sun's heat is kept in the frame and 

 forces the seedlings. At night it may be necessary at first 

 to put an extra covering over the frame. Later, on warm 

 days, the window roof should be raised and the air allowed 

 to enter. Still later the window may be taken off during the 

 day and replaced at night or on cool days. Plants raised 

 here are more hardy and healthy than those started indoors. 

 If too thick they should be pricked out and transplanted 

 to another frame. The plants started earlier indoors may 

 be taken up and set in the cold-frame. 



Hot-bed: This resembles a cold-frame, only it is deeper 

 and has a thick foundation of about two feet of fresh horse 

 manure, under the growing soil of about four or five inches. 

 It is covered with glass. The purpose of the manure is to 

 produce an artificial heat by its decay or fermentation. 

 The box may be set deeply into the ground, or raised and 

 banked up with manure. At first the temperature may be 

 too warm for sowing, but after a few days, when the average 

 temperature is about 80 degrees, the seeds may be sown or 

 the seedlings transplanted to it. A thermometer should be 

 hung in the hot-bed, and when it registers more than the 

 above temperature, the glass should be raised more or less to 

 ventilate. As the hot-bed requires considerable care and 

 judgment, it is not advisable to let the httle children grow 

 plants in it. Plants raised in a hot-bed often suffer a severe 

 setback in their development, unless very carefully hard- 



