138 Principles of Plant Culture. 



218. Injudicious Watering is perhaps the most com- 

 mon cause of failure in growing potted plants. The 

 amateur too often assumes that the chief need of the 

 plants is frequent watering, and so gives water in spoon- 

 ful doses as the surface soil of the pot appears dry, 

 without observing the state of the soil beneath. The 

 roots of the plants in the meantime may be smother- 

 ing in water-logged soil or starving from drought. If, 

 owing to inexperience, the condition of the soil can- 

 not be determined by the means above noted, the soil 

 may be tipped out upon the hand without materially 

 disturbing the roots of the plant, by reversing the pot 

 and gently striking its rim on the edge of the bench or 

 table. The real condition can then be readily de- 

 termined. 



219. Copious Waterings at Considerable Intervals 

 are Preferable to frequent slight waterings. It should 

 never be forgotten that air is as essential as water to 

 the well-being of roots (89), and that the soil, however 

 porous, requires occasional ventilation (93). A con- 

 siderable quantity of water poured upon the surface 

 soil of a potted plant, in passing downward not only 

 thoroughly moistens the soil particles, but acts like a 

 piston, forcing the satiated air of the soil cavities ahead 

 of it and out through the drainage hole at the bottom of 

 the pot, while fresh air enters from above as the sur- 

 plus water passes out beneath. Manure water should 

 not often be used, as there is danger in giving the plant 

 too much food. 



220. Rapidly-Growing Plants Require More Water 

 and are less liable to suffer from over-watering than 



