104 GARDENING FOR PLEASURE. 



tery, cork, or other material to become more dry. Light 

 and air are essential to vigorous growth, deluging -with 

 water when in active growth, but never closing top venti- 

 lation ; never having a stagnant atmosphere ; gradually 

 withholding water as the growth approaches maturity, 

 and then only enough to keep from shriveling. As to 

 time for re-potting, the cultivator is guided by the com- 

 mencement of growth. Plants should always be under- 

 potted as long as the plant is not top-heavy, such as 

 Cattleyas, Lcelias, Dendrobiums, etc. ; a top dressing is 

 all that is needful. Calanthe, Phaius, etc., are re-pot- 

 ted annually. 



Insects, such as thrips and aphis, are kept under by 

 filling the evaporating pans, or other vessels, with chopped 

 tobacco stems covered with water. Slugs are kept down 

 by placing lettuce leaves, sliced potatoes or carrots on 

 the pots, which examine daily, and destroy. Eoaches and 

 water bugs may be killed by mixing roach poison with 

 molasses, and placing it on oyster shells at convenient 

 points in the greenhouse. These same remedies will be 

 found effective against insects attacking any kind of 

 greenhouse plant. 



CHAPTER XIX. 

 UNHEALTHY PLANTS THE REMEDY. 



WHENEVER plants begin to drop their leaves, it is cer- 

 tain that their health has been injured. This may be due 

 to over-potting, over-watering, over-heating, too much 

 cold, or the application of such stimulants as guano, or 

 to some other cause which has destroyed the fine rootlets 

 by which the plant feeds, and induced disease that may 

 lead to death. The case is not usually important enough 



