172 
THE COTTAGE GARDENER. 
[J UNE 19. 
Some queries relative to the premature dropping of 
Fuchsia buds, which will he found in our last page, 
added to an enquiry as to the temperature water should 
possess when applied to the roots of plants, induces us 
to resume the observations we somewhat abruptly con¬ 
cluded at page 94 of our last volume. 
It has been maintained, that water is the sole food of 
plants; but all experiments are inconclusive which are 
presented as supporting the theory. In the first place, 
all waters contain earthy, saline, and organic matters: 
even distilled water is not pure, as Sir H. Davy has 
proved; and rain water, Margraaf, Liebig, and others, 
have demonstrated to be much less so. No plants, except 
water plants, growing in water only, will ever perfect 
seed; and the facts, that different plants affect different 
soils, and that a soil will not bear through a series of 
years the same crop, whereas it will bear a rotation of 
different ones, demonstrate that they each take different 
kinds of food from the earth, and not that universal 
one, water, which is ever present and renewed. 
So far, indeed, from water being the sole food of 
plants, they are injured and destroyed by its superabun¬ 
dance in the soils sustaining them. Such soils are 
always colder than well-drained soils, inasmuch as that 
the same quantity of caloric (heat) which will warm 
the earth four degress, will only warm water one degree— 
or, to use the language of the chemist, the capacity for 
heat of water is four times greater than that of the 
earths. Secondly, the vegetable decomposing matters 
in a soil, where water is superabundant, give out carbu- 
retted hydrogen, acetic, gallic, and other acids, instead 
of carbonic acid gas and ammonia,—products essential 
to healthy vegetation. Palliatives for such evils are the 
application of lime, or its carbonate, chalk, to the soils 
in which these acids have been generated; and, indeed> 
after they have been formed, such an application is 
essential, though the radical cure and preventive of 
recurrence—thorough drainage, be adopted. 
To plants in pots, good drainage is not less essential 
than to those in our borders. To secure this, not only 
should at least two inches of rubbly materials and char¬ 
coal be placed beneath the soil put into the pots, but 
the soil itself should be allowed to retain its pebbles, in¬ 
stead of having them sifted out, as was the ancient prac¬ 
tice. 
Drainage, however, is not the only desideratum to 
potted plants, for they have many other difficulties to 
contend against, from which those in the open soil are 
preserved. The open soil is always a few degrees warmer 
than the exterior air; but, owing to the evaporation 
from the sides of garden-pots, this is rarely the case 
with the soil in them. To preserve this salutary warmth 
to the roots, a double pot has been suggested. 
The importance of following the dictate of nature, to 
keep the roots of plants, natives of the temperate zone, 
as warm or warmer than the branches, has been too 
much neglected by the gardener in his forcing depart¬ 
ment. In the vinery, for example, the stem and roots 
are too often exposed to the rigour of winter, whilst the 
buds are expanding within the glass shelter in a tem¬ 
perature of 00°. A vine so treated is like the felled elm, 
which, allowed to retain its bark, though rootless, puts 
forth its leaves in the spring, expands its buds, and 
advances through the first stages of growth merely from 
the inspissated sap stored within its stem and branches. 
This is no mere suggestion of fancy; for repeated ex¬ 
periments have shown that hothouse vines, with their j 
roots thus kept torpid by exposure to cold, had not their 
buds burst; whilst other vines, treated in all respects 
similarly, but with their roots kept genially warm, were j 
actually in bloom. 
Although an excess of water applied to the roots of 
plants is injurious to them, yet all of them are benefited 
by a due supply of that liquid, and that supply has to 
be regulated by the amount of their daily transpiration. 
The gardener knows that this differs in every species, 
and during different seasons. For instance, in a dry hot 
day, a sunflower, three feet and a half high, transpired 
1 lb. 4 oz., being seventeen times more than the human 
body; during a hot dry night, 3 ozs.: during a dewy 
night there was no transpiration; and during a rainy 
night it absorbed 3 ozs. 
Therefore the gardener finds it best to apply water 
during dry weather, early in the morning, just before the 
chief demand occurs, which is from six a.m. till two in 
the afternoon; and during moist weather he refrains 
from the application entirely. Then, again, the gardener 
keeps his Agaves and other fleshy-leaved plants in a dry 
stove, for they transpire but sparingly in proportion to 
their mass, and require watering biff seldom, and then 
abundantly; for they take up, as in their native sandy 
soils, a large supply, and retain it pertinaciously in 
defiance of the long-protracted droughts to which they 
are exposed. 
In the same species we have always found varieties 
transpire abundantly, and require a larger supply of 
water in proportion to the extent of their transpiring 
surface. Thus the broad-leaved fuchsias and pelargo¬ 
niums transpire from two to three times as much as those 
varieties which have smaller and less abundant foliage 
Then, again, as to the temperature at which water 
should be applied, it may be taken as a general rule, 
that it should be 5° warmer than the soil in which the 
roots are growing. This, of course, varies, for, as we 
have observed in The Cottage Gardeners Dictionary , 
“Every plant obviously will have a particular bottom 
heat most congenial to it. Plants growing in open 
plains, as at the Cape of Good Hope, will require a 
higher bottom heat than those growing in the shade of 
the South American forests, though the temperature of 
the air out of the shade maybe the same in each country. 
That gardener will succeed in exotic plant-culture best, 
who, among his other knowledge, has ascertained the 
relative temperature of the air and soil, in which any 
given plant grows naturally. At present, such informa¬ 
tion from actual observation is not obtainable, but it is 
not difficult to ascertain the maximum and minimum I 
temperature of the air of a country; and this being 
obtained, the gardener may adopt this as a safe rule :— 
Let flie bottom heat for plants of that country be 5° 
