VEGETABLE PLANTS. 33 



loosen it, and, in addition, the sun's rays will 

 to a greater extent be absorbed on account of 

 the dark color of the surface, and the bed con- 

 sequently be made warmer. It is not neces- 

 sary to cover these beds entirely with glass. 

 The shutters, already described, may be made 

 to do good service here, and the amount of 

 glass at command made to go twice as far. 

 The plants should not be pulled until they 

 are quite well rooted, and if they can then be 

 transplanted into another bed for a couple of 

 weeks, they will be greatly improved, though 

 few of the sweet-potato plants offered for sale 

 are transplanted. Care must be exercised in 

 pulling, or separating the plant from the tuber, 

 not to displace the tuber or break off the sprouts 

 which may have started for a second crop. 



As this work may fall into the hands of 

 many readers who may desire to try growing a 

 few sweet potatoes at the north, a few words 

 on the subject of setting the plants, and the 

 treatment of them, though hardly within the 

 scope of the work, may not be entirely out 

 of place. Never lose sight of the fact that 

 the sweet potato is, by nature, a semi-tropical 

 plant ; therefore everything you can do to in- 



