128 Principles of Plant Culture. 
the earthy particles after percolation has nearly ceased, 
(capillary water). Such water is well aerated because it is 
interspersed with cavities that are filled with air. In the 
open ground, the remedy for excessive soil water may usually 
be found in underground drainage. But the same trouble 
often occurs in potted plants, as the result of too compact 
soil or too copious watering. The expert recognizes this 
condition by a sour odor of the soil, by lifting the pot, or 
by tapping the pot with his knuckle. If the soil is soggy, 
the weight will betray the fact, or the sound given out by 
the pot will be that of a compact mass, instead of a more or 
less hollow body, as is the case with a pot of well-aerated 
soil. To remedy the evil, repot the plant in fresh soil, of a 
proper condition of moisture, providing abundant drainage. 
at the bottom of the pot (412). 
219. 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 spoonful 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 smothering in water-logged soil, or 
starving from drought. If, owing to inexperience, the con- 
dition of the soil cannot 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 determined. 
220. Rapidly-Growing Plants Require More Water, 
and are less liable to suffer from over-watering, than slower- 
growing ones. During the rest period (173), plants should 
be given very little water. 
