98 GARDENING FOB PLEASURE. 



CHAPTER XXX. 



GREENHOUSES OR PITS, WITHOUT ARTIFICIAL HEATING. 



The directions given for heating greenhouses by hot 

 water or by flues, apply of course only to sections of the 

 country where the temperature during the winter months 

 makes heating a necessity. In many of the southern 

 states there is no need of artificial heat. A greenhouse 

 tightly glazed and placed against a building where it is 

 sheltered from the north and north-west will keep out 

 frost when the temperature does not fall lower than 25 

 degrees above zero, and if light wooden shutters are used 

 to cover the glass, all those classed as "greenhouse" 

 plants will be safe even at 10 

 degrees lower, provided, of 

 course, that the conservatory 

 is attached to the dwelling, 

 as shown in fig. 38. Another 

 cheap and simple method 

 of keeping plants during 

 winter in mild latitudes is by Fi S- ^.-SUNKEN PET. 



the use of the sunken pit or deep frame, which affords 

 the needed protection even more completely than the eleva- 

 ted greenhouse. This is formed by excavating the soil to 

 the depth of from 18 to 36 inches, according to the size 

 of the plants it is intended to contain. A convenient 

 width is 6 feet, the ordinary length of a hot-bed sash, 

 and of such length as may be desired. Great care must 

 be taken that the ground is such that no water will stand 

 in the pit ; if the soil is moist it should be drained. The 

 sides of the pit may be either walled up by a 4 or 8-inch 

 course of brick work, or planked up as may be preferred, 

 but in either case the lack wall should be raised about 

 eighteen inches, and the front about six inches above the 



