2l6 
Garden Work 
generally taught to tap the pots, and if they emit a bell- 
like sound he is told they require water. Afterwards, as 
he gains experience, he can tell to some extent when a 
plant requires water by the appearance of the surface of 
the soil. But a good gardener ought to know more about 
this subject. 
To begin with, he places crocks in his pots to drain 
away the superfluous water; then mixes his soil in such 
a way that there are sufficient gritty particles (sand) in it 
to ensure that the superfluous water will drain through it. 
But we know that plants require water at all times, to a 
greater or less extent, and therefore we must supply it 
when it is required, and only then. When we water a 
perfectly drained pot, where the soil is suitably mixed, a 
considerable portion of the water will pass through. This 
is necessary to ensure that the whole of the soil has been 
watered. All the water, however, does not pass through. 
A tiny film is left round every particle of soil, but between 
the particles are the essential air spaces. It is this film 
of water round the particles of soil which supplies the plant. 
The rootlets, with their absorbing root hairs, cling to the 
soil and suck up this film and the liquid plant food with it. 
As soon as this water is exhausted, more must be supplied, 
or the cells will get partially emptied (for water is always 
being given off in transpiration during the growing season), 
and the plants will thus droop. If plants show signs of 
drooping they should be watered at once, but even then, 
with some plants, the mischief will be done. We must, 
therefore, understand our plants and the conditions of their 
growth, and be able to determine when to give the neces- 
sary water before that previously supplied has been used 
