17C 
THE THEORY OF HEAT AND COLD IN PLANT HOUSES. 
worst thing that can be clone for science, to 
set up a novel practice, and say it is right for 
every thing : plants are as various in their 
constitutions as animals, and it is worse than 
folly to suppose any system can apply well to 
all of them. There are weighty objections 
to the one- shift system as a general thing ; 
first, because all the time a plant is growing 
it is useless until it arrives at the size when it 
is a match for the pot; secondly, the enormous 
disproportion of the pots to houses of present 
construction would curtail the number of 
plants to be grown in the proportion of five- 
sixths ; thirdly, it deprives us of the enjoy- 
ment of the beautiful plants which bloom 
when small, and continue to bloom annually 
for many years before they arrive at their full 
size. Let us take the subjects of heaths, which 
from the time they are in good proportion to 
a forty-eight sized pot are beautiful ; they are 
changed from time to time, from one pot to 
another, and are still beautiful and in good 
proportion to the pot they bloom in ; and we 
maintain, that from the time they first bloom, 
however small they may be, they are desirable. 
Let the same small plants be placed in a peck 
pot, and there they must remain useless fix- 
tures, until they have arrived at the size 
that is proportionable, and then, if we follow 
up the subject, what is to become of them 
when in perfection ? why they must die or 
be shifted into larger, so that the advocates of 
the plan beat themselves by aiming at too 
much. There was nothing new in making 
very great changes in the sizes of pots : the 
practice with some things is very old indeed. 
Carnations and Piccotees have ever been 
grown with but one shift ; the layers are 
stored in large sixty sized, or small forty-eight 
sized pots, and in the spring shifted at once in 
pots of number 12 size. Again, climbing- 
plants, with fancy trellises, have been long 
grown upon that principle ; the trellis being a 
fixture to the large pots, the plant in its smallest 
state has been by many put at once into the 
pot it was to be perfected in. Many other 
subjects will grow well with a single shift ; 
but if gentlemen's houses are to be filled with 
peck pots, and plants, begun as rooted cuttings, 
to stick there till they are large enough to 
match them, away goes all the diversity of 
collections, and nine-tenths must be thrown 
away to make room for the remainder. All 
that need be said upon the subject is, that the 
system is very well as a plaything, to be used 
by those who like it, but that it is perfectly 
unnecessary, and as a general system both 
inconvenient and incompatible with the beauty 
of a house, and the gratification of the owners. 
Nobody can dispute the fact that a plant 
likes room, else how is it that they grow so 
much better in the open ground than in pots? 
If plants like room, it is a good reason for 
giving them plenty, but this plenty must be 
regulated by the means at hand, and the pur- 
poses to answer. If, as in most gentlemen's 
establishments, there is required a constant 
succession of blooming objects, it is better to 
have all these of available sizes, than to shut 
ourselves out by attempting novelties which 
preclude the use of those we have; and while 
plants may be for years handsome and pro- 
portionate, available as ornaments and easily 
removed, it does seem 1 a crazy proceeding to 
put them into half-a-hundred weight of soil, 
which makes them fixtures, and ugly ones, 
until they have grown up to the pot. But 
to grow a plant as well with half-a-dozen 
shii'ts, as we can with one, we have to be 
careful on sundry points: first, they must never 
suffer an hour for want of water ; secondly, 
they must be shifted as soon as the roots reach 
the sides of the pot ; thirdly, there must be 
great care taken that the drainage is free ; 
fourthly, the sides of the pot must not receive 
the heat of the sun. With these conditions 
we have seen, and shall see again, the plant 
of many shifts equal in beauty in all its stages 
to the plant of the peck pot. 
THE THEORY OF HEAT AND COLD IN 
PLANT HOUSES. 
A good deal may be written on this subject, 
for there is much to be learned, but I shall 
confine myself to one single point, little at- 
tended to, little thought of, and by many never 
considered at all ; I mean the necessity of 
lowering the temperature at night. In general, 
and I have visited many private establish- 
ments, the temperature of the green-house is 
raised, instead of lowered. Fires are lighted 
in the evening, and when all is dark the tem- 
perature is raised, and the effect perfectly 
unnatural; if it were possible, the temperature 
of a green-house in the dark should be five or 
ten degrees colder than in the daylight ; and 
it is in the nights only that plants get drawn 
and of bad colour. What is the condition of 
a plant out of doors ? It has all the heat 
during the day, and all that is above ground 
receives the cold during the night, while its 
roots in the earth suffer no diminution, for 
below the surface the ground is as warm as 
it was in the day-time. Let a geranium 
be turned out in May, and let another be 
kept in the house, and that out of doors beats 
one under glass in every respect — it is less 
drawn and is a better colour. It has the bene- 
fit of a cooler atmosphere all through the night, 
while the one under glass is shut up out of 
the wind, and in the warmth, without even 
the benefit of the air which it receives during. 
